# Averages/Mode

(Redirected from Average/Mode)
Averages/Mode
You are encouraged to solve this task according to the task description, using any language you may know.

Write a program to find the mode value of a collection.

The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.

If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriate or possible to support an unspecified value type, use integers.

## 11l

Translation of: Python
F modes(values)
DefaultDict[Int, Int] count
L(v) values
count[v]++
V best = max(count.values())
R count.filter(kv -> kv[1] == @best).map(kv -> kv[0])

print(modes([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]))
print(modes([1, 1, 2, 4, 4]))
Output:
[6]
[1, 4]


## Action!

DEFINE MAX="100"
INT ARRAY keys(MAX)
INT ARRAY values(MAX)
BYTE count

PROC PrintArray(INT ARRAY a INT size)
INT i

Put('[)
FOR i=0 TO size-1
DO
IF i>0 THEN Put(' ) FI
PrintI(a(i))
OD
Put(']) PutE()
RETURN

PROC ClearMap()
count=0
RETURN

INT i,index

index=-1
IF count>0 THEN
FOR i=0 TO count-1
DO
IF keys(i)=a THEN
index=i EXIT
FI
OD
FI
IF index=-1 THEN
keys(count)=a
values(count)=1
count==+1
ELSE
values(index)==+1
FI
RETURN

PROC Mode(INT ARRAY a INT aSize INT ARRAY m INT POINTER mSize)
INT i,mx

ClearMap()
FOR i=0 TO aSize-1
DO
OD

mx=0
FOR i=0 TO count-1
DO
IF values(i)>mx THEN
mx=values(i)
FI
OD

mSize^=0
FOR i=0 TO count-1
DO
IF values(i)=mx THEN
m(mSize^)=keys(i)
mSize^==+1
FI
OD
RETURN

PROC Test(INT ARRAY a INT size)
INT ARRAY m(MAX)
INT mSize

PrintE("Array:") PrintArray(a,size)
Mode(a,size,m,@mSize)
PrintE("Mode:") PrintArray(m,mSize)
PutE()
RETURN

PROC Main()
INT ARRAY a=[1 3 5 7 3 1 3 7 7 3 3]
INT ARRAY b=[7 13 5 13 7 2 7 10 13]
INT ARRAY c=[5]

Test(a,11)
Test(b,9)
Test(c,1)
RETURN
Output:
Array:
[1 3 5 7 3 1 3 7 7 3 3]
Mode:
[3]

Array:
[7 13 5 13 7 2 7 10 13]
Mode:
[7 13]

Array:
[5]
Mode:
[5]


## ActionScript

This implementation does not work with arbitrary collections. However, it works with arrays containing mixed data, including strings and other arrays.

function Mode(arr:Array):Array {
//Create an associative array to count how many times each element occurs,
//an array to contain the modes, and a variable to store how many times each mode appears.
var count:Array = new Array();
var modeList:Array;
var maxCount:uint=0;
for (var i:String in arr) {
//Record how many times an element has occurred. Note that each element in the cuont array
//has to be initialized explicitly, since it is an associative array.
if (count[arr[i]]==undefined) {
count[arr[i]]=1;
} else {
count[arr[i]]++;
}
//If this is now the most common element, clear the list of modes, and add this element.
if(count[arr[i]] > maxCount)
{
maxCount=count[arr[i]];
modeList = new Array();
modeList.push(arr[i]);
}
//If this is a mode, add it to the list.
else if(count[arr[i]] == maxCount){
modeList.push(arr[i]);
}
}
return modeList;
}


generic
type Element_Type is private;
type Element_Array is array (Positive range <>) of Element_Type;
package Mode is

function Get_Mode (Set : Element_Array) return Element_Array;

end Mode;


with Ada.Containers.Indefinite_Vectors;

package body Mode is

-- map Count to Elements
(Element_Type => Element_Array,
Index_Type => Positive);

procedure Add (To : in out Count_Vectors.Vector; Item : Element_Type) is
use type Count_Vectors.Cursor;
Position : Count_Vectors.Cursor := To.First;
Found    : Boolean              := False;
begin
declare
Elements : Element_Array := Count_Vectors.Element (Position);
begin
for I in Elements'Range loop
if Elements (I) = Item then
Found := True;
end if;
end loop;
end;
Position := Count_Vectors.Next (Position);
end if;
end loop;
if Position /= Count_Vectors.No_Element then
-- element found, remove it and insert to next count
declare
New_Position : Count_Vectors.Cursor :=
Count_Vectors.Next (Position);
begin
-- remove from old position
declare
Old_Elements : Element_Array :=
Count_Vectors.Element (Position);
New_Elements : Element_Array (1 .. Old_Elements'Length - 1);
New_Index    : Positive      := New_Elements'First;
begin
for I in Old_Elements'Range loop
if Old_Elements (I) /= Item then
New_Elements (New_Index) := Old_Elements (I);
New_Index                := New_Index + 1;
end if;
end loop;
To.Replace_Element (Position, New_Elements);
end;
-- new position not already there?
if New_Position = Count_Vectors.No_Element then
declare
New_Array : Element_Array (1 .. 1) := (1 => Item);
begin
To.Append (New_Array);
end;
else
declare
Old_Elements : Element_Array :=
Count_Vectors.Element (New_Position);
New_Elements : Element_Array (1 .. Old_Elements'Length + 1);
begin
New_Elements (1 .. Old_Elements'Length) := Old_Elements;
New_Elements (New_Elements'Last)        := Item;
To.Replace_Element (New_Position, New_Elements);
end;
end if;
end;
else
Position := To.First;
if Position = Count_Vectors.No_Element then
declare
New_Array : Element_Array (1 .. 1) := (1 => Item);
begin
To.Append (New_Array);
end;
else
declare
Old_Elements : Element_Array :=
Count_Vectors.Element (Position);
New_Elements : Element_Array (1 .. Old_Elements'Length + 1);
begin
New_Elements (1 .. Old_Elements'Length) := Old_Elements;
New_Elements (New_Elements'Last)        := Item;
To.Replace_Element (Position, New_Elements);
end;
end if;
end if;

function Get_Mode (Set : Element_Array) return Element_Array is
Counts : Count_Vectors.Vector;
begin
for I in Set'Range loop
end loop;
return Counts.Last_Element;
end Get_Mode;

end Mode;


example use:

with Ada.Text_IO;
with Mode;
procedure Main is
type Int_Array is array (Positive range <>) of Integer;
package Int_Mode is new Mode (Integer, Int_Array);

Test_1 : Int_Array := (1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6);
Result : Int_Array := Int_Mode.Get_Mode (Test_1);
begin
for I in Test_1'Range loop
if I /= Test_1'Last then
end if;
end loop;
for I in Result'Range loop
if I /= Result'Last then
end if;
end loop;
end Main;

Output:
Input:  1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6
Result: 2, 3

## ALGOL 68

Library: ALGOL 68-rows

This sample defines an operator to return the mode(s) of an integer array. Additional operators cound be defined for other array types.
Note the source of rows.incl.a68 (containing the QUICKSORT and SHOW operators) is available on a page in Rosetta Code, see the above link.

BEGIN # find the mode (most frequent value) of a set of items                #
PR read "rows.incl.a68" PR               # include row (array) utilities #
# returns the mode(s) of a - similar operators could be defined for      #
#                            types other than INT                        #
OP MODEOF = ( []INT a )[]INT:
IF LWB a > UPB a THEN []INT() # no data                               #
ELSE                          # have data                             #
[ LWB a : UPB a ]INT sorted data := a;
QUICKSORT sorted data FROMELEMENT LWB sorted data TOELEMENT UPB sorted data;
INT distinct count = BEGIN  # count the number of distinct values #
INT count := 1;
INT value := sorted data[ LWB sorted data ];
FOR i FROM LWB sorted data + 1 TO UPB sorted data DO
IF value /= sorted data[ i ] THEN
count +:= 1;
value  := sorted data[ i ]
FI
OD;
count
END;
INT current value := sorted data[ LWB sorted data ];
INT max count     := 0;
INT current count := 1;
INT s pos         := LWB sorted data + 1;
# allow for the maximum possible number of modes                  #
[ 1 : distinct count ]INT modes;
INT mode count    := 1;
modes[ 1 ]        := current value;
WHILE s pos <= UPB sorted data DO
s pos +:= 1;
WHILE IF s pos > UPB sorted data
THEN FALSE
ELSE sorted data[ s pos ] = current value
FI
DO
current count +:= 1;
s pos         +:= 1
OD;
IF current count > max count THEN
max count                 := current count;
modes[ mode count  := 1 ] := sorted data[ s pos - 1 ]
ELIF current count = max count THEN
modes[ mode count +:= 1 ] := sorted data[ s pos - 1 ]
FI;
current count := 0;
IF s pos <= UPB sorted data THEN
current value := sorted data[ s pos ]
FI
OD;
modes[ 1 : mode count ]
FI # MODEOF # ;

# test cases as in the 11l sample                                        #
SHOW MODEOF []INT( 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17 );print( ( newline ) );
SHOW MODEOF []INT( 1, 1, 2, 4, 4 )                     ;print( ( newline ) );
# test cases as in the Action! sample                                    #
SHOW MODEOF []INT( 1, 3, 5, 7, 3, 1, 3, 7, 7, 3, 3 )   ;print( ( newline ) );
SHOW MODEOF []INT( 7, 13, 5, 13, 7, 2, 7, 10, 13 )     ;print( ( newline ) );
SHOW MODEOF []INT( 5 )                                 ;print( ( newline ) );
SHOW MODEOF []INT( 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9 )   ;print( ( newline )

END
Output:
 6
1 4
3
7 13
5
9


## APL

mode←{{s←⌈/⍵[;2]⋄⊃¨(↓⍵)∩{⍵,s}¨⍵[;1]}{⍺,≢⍵}⌸⍵}


## AppleScript

This works with both lists and records containing numbers and/or text values.

use AppleScript version "2.3.1" -- Mac OS X 10.9 (Mavericks) or later (for these 'use' commands).
use sorter : script "Shell sort" -- https://www.rosettacode.org/wiki/Sorting_algorithms/Shell_sort#AppleScript

on modeOf(listOrRecord)
-- Extract and sort numbers and text separately, then concatenate the results to get a single list of values.
set theNumbers to listOrRecord's numbers
tell sorter to sort(theNumbers, 1, -1)
set theTexts to listOrRecord's text
tell sorter to sort(theTexts, 1, -1)
script o
property values : theNumbers & theTexts
property mode : {}
end script

-- Identify the most frequently occurring value(s).
if (o's values is not {}) then
set i to 1
set currentValue to beginning of o's values
set maxCount to 1
repeat with j from 2 to (count o's values)
set thisValue to item j of o's values
if (thisValue is not currentValue) then
set thisCount to j - i
if (thisCount > maxCount) then
set o's mode to {currentValue}
set maxCount to thisCount
else if (thisCount = maxCount) then
set end of o's mode to currentValue
end if
set i to j
set currentValue to thisValue
end if
end repeat
if (j + 1 - i > maxCount) then
set o's mode to {currentValue}
else if (j + 1 - i = maxCount) then
set end of o's mode to currentValue
end if
end if

return o's mode
end modeOf

-- Test code:
-- With a list:
modeOf({12, 4, "rhubarb", 88, "rhubarb", 17, "custard", 4.0, 4, 88, "rhubarb"})
--> {4, "rhubarb"}

-- With a record:
modeOf({a:12, b:4, c:"rhubarb", d:88, e:"rhubarb", f:17, g:"custard", h:4.0, i:4, j:88})
--> {4}


## Arturo

getMode: function [arr][
freqs: new #[]
loop arr 'i [
k: to :string i
if not? key? freqs k -> set freqs k 0
freqs\[k]: (freqs\[k]) + 1
]
maximum: max values freqs
select keys freqs 'i -> maximum = freqs\[i]
]

print getMode [1 3 6 6 6 6 7 7 12 12 17]
print getMode [1 1 2 4 4]

Output:
6
1 4

## AutoHotkey

Search autohotkey.com: [1]
Source: AutoHotkey forum by Laszlo

MsgBox % Mode("1 2 3")
MsgBox % Mode("1 2 0 3 0.0")
MsgBox % Mode("0.1 2.2 -0.1 0.22e1 2.20 0.1")

Mode(a, d=" ") { ; the number that occurs most frequently in a list delimited by d (space)
Sort a, ND%d%
Loop Parse, a, %d%
If (V != A_LoopField) {
If (Ct > MxCt)
MxV := V, MxCt := Ct
V := A_LoopField, Ct := 1
}
Else Ct++
Return Ct>MxCt ? V : MxV
}


## AWK

#!/usr/bin/gawk -f
{
# compute histogram
histo[$1] += 1; }; function mode(HIS) { # Computes the mode from Histogram A max = 0; n = 0; for (k in HIS) { val = HIS[k]; if (HIS[k] > max) { max = HIS[k]; n = 1; List[n] = k; } else if (HIS[k] == max) { List[++n] = k; } } for (k=1; k<=n; k++) { o = o""OFS""List[k]; } return o; } END { print mode(histo); };  cat modedata.txt 0 3 6 aa 3 6 aa 3 aa 6 7 1 as@mini10:~/src/RosettaCode$ ./mode.awk modedata.txt
6 aa 3


## BBC BASIC

      DIM a(10), b(4)
a() = 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17
b() = 1, 2, 4, 4, 1

DIM modes(10)
PRINT "Mode(s) of a() = " ;
FOR i% = 1 TO FNmodes(a(), modes())
PRINT ; modes(i%) " " ;
NEXT
PRINT
PRINT "Mode(s) of b() = " ;
FOR i% = 1 TO FNmodes(b(), modes())
PRINT ; modes(i%) " " ;
NEXT
PRINT
END

DEF FNmodes(a(), m())
LOCAL I%, J%, N%, c%(), max%
N% = DIM(a(),1)
IF N% = 0 THEN m(1) = a(0) : = 1
DIM c%(N%)
FOR I% = 0 TO N%-1
FOR J% = I%+1 TO N%
IF a(I%) = a(J%) c%(I%) += 1
NEXT
IF c%(I%) > max% max% = c%(I%)
NEXT I%
J% = 0
FOR I% = 0 TO N%
IF c%(I%) = max% J% += 1 : m(J%) = a(I%)
NEXT
= J%

Output:
Mode(s) of a() = 6
Mode(s) of b() = 1 4

## BQN

BQNcrate lists two functions for mode. Of these, the first is faster.

Mode1 ← ⌈´⊸=∘⊒⊸/
Mode2 ← ⊏∘⊑˘·(⌈´⊸=≠¨)⊸/⊐⊸⊔

arr ← 1‿1‿1‿1‿2‿2‿2‿3‿3‿3‿3‿4‿4‿3‿2‿4‿4‿4‿5‿5‿5‿5‿5
•Show Mode1 arr
•Show Mode2 arr
⟨ 3 4 5 ⟩
⟨ 3 4 5 ⟩

## C

Using an array of doubles. If another data type is desired, the cmp_dbl and vcount definitions should be changed accordingly.

#include <stdio.h>
#include <stdlib.h>

typedef struct { double v; int c; } vcount;

int cmp_dbl(const void *a, const void *b)
{
double x = *(const double*)a - *(const double*)b;
return x < 0 ? -1 : x > 0;
}

int vc_cmp(const void *a, const void *b)
{
return ((const vcount*)b)->c - ((const vcount*)a)->c;
}

int get_mode(double* x, int len, vcount **list)
{
int i, j;
vcount *vc;

/* sort values */
qsort(x, len, sizeof(double), cmp_dbl);

/* count occurence of each value */
for (i = 0, j = 1; i < len - 1; i++, j += (x[i] != x[i + 1]));

*list = vc = malloc(sizeof(vcount) * j);
vc[0].v = x[0];
vc[0].c = 1;

/* generate list value-count pairs */
for (i = j = 0; i < len - 1; i++, vc[j].c++)
if (x[i] != x[i + 1]) vc[++j].v = x[i + 1];

/* sort that by count in descending order */
qsort(vc, j + 1, sizeof(vcount), vc_cmp);

/* the number of entries with same count as the highest */
for (i = 0; i <= j && vc[i].c == vc[0].c; i++);

return i;
}

int main()
{
double values[] = { 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 12, 12, 17 };
#	define len sizeof(values)/sizeof(double)
vcount *vc;

int i, n_modes = get_mode(values, len, &vc);

printf("got %d modes:\n", n_modes);
for (i = 0; i < n_modes; i++)
printf("\tvalue = %g, count = %d\n", vc[i].v, vc[i].c);

free(vc);
return 0;
}

Output:
got 2 modes:
value = 6, count = 4
value = 12, count = 4

## C#

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace Test
{
class Program
{

static void Main(string[] args)
{
/*
* We Use Linq To Determine The Mode
*/
List<int> myList = new List<int>() { 1, 1, 2, 4, 4 };

var query =     from numbers in myList //select the numbers
group numbers by numbers //group them together so we can get the count
into groupedNumbers
select new { Number = groupedNumbers.Key, Count = groupedNumbers.Count() }; //so we got a query
//find the max of the occurence of the mode
int max = query.Max(g => g.Count);
IEnumerable<int> modes = query.Where(x => x.Count == max).Select(x => x.Number);//match the frequence and select the number
foreach (var item in modes)
{
Console.WriteLine(item);
}

}

}

}


## C++

Works with: g++ version 4.3.2
#include <iterator>
#include <utility>
#include <algorithm>
#include <list>
#include <iostream>

// helper struct
template<typename T> struct referring
{
referring(T const& t): value(t) {}
template<typename Iter>
bool operator()(std::pair<Iter, int> const& p) const
{
return *p.first == value;
}
T const& value;
};

// requires:
// FwdIterator is a ForwardIterator
// The value_type of FwdIterator is EqualityComparable
// OutIterator is an output iterator
// the value_type of FwdIterator is convertible to the value_type of OutIterator
// [first, last) is a valid range
// provides:
// the mode is written to result
template<typename FwdIterator, typename OutIterator>
void mode(FwdIterator first, FwdIterator last, OutIterator result)
{
typedef typename std::iterator_traits<FwdIterator>::value_type value_type;
typedef std::list<std::pair<FwdIterator, int> > count_type;
typedef typename count_type::iterator count_iterator;

// count elements
count_type counts;

while (first != last)
{
count_iterator element = std::find_if(counts.begin(), counts.end(),
referring<value_type>(*first));
if (element == counts.end())
counts.push_back(std::make_pair(first, 1));
else
++element->second;
++first;
}

// find maximum
int max = 0;
for (count_iterator i = counts.begin(); i != counts.end(); ++i)
if (i->second > max)
max = i->second;

// copy corresponding elements to output sequence
for (count_iterator i = counts.begin(); i != counts.end(); ++i)
if (i->second == max)
*result++ = *i->first;
}

// example usage
int main()
{
int values[] = { 1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6 };
median(values, values + sizeof(values)/sizeof(int),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
return 0;
}

Output:
2 3


## Clojure

(defn modes [coll]
(let [distrib (frequencies coll)
[value freq] [first second] ; name the key/value pairs in the distrib (map) entries
sorted (sort-by (comp - freq) distrib)
maxfq (freq (first sorted))]
(map value (take-while #(= maxfq (freq %)) sorted))))


Or a one-liner solution

(defn modes [coll]
(->> coll frequencies (sort-by val >) (partition-by val) first (map key)))


## CoffeeScript

mode = (arr) ->
# returns an array with the modes of arr, i.e. the
# elements that appear most often in arr
counts = {}
for elem in arr
counts[elem] ||= 0
counts[elem] += 1
max = 0
for key, cnt of counts
max = cnt if cnt > max
(key for key, cnt of counts when cnt == max)

console.log mode [1, 2, 2, 2, 3, 3, 3, 4, 4]


## Common Lisp

The following returns a list of the modes of a sequence as the primary value, and the frequency as the secondary value. E.g., (mode '(a b c d a b c a b)) produces (A B) and 3. hash-table-options can be used to customize the hash table, e.g., to specify the test by which elements are compared.

(defun mode (sequence &rest hash-table-options)
(let ((frequencies (apply #'make-hash-table hash-table-options)))
(map nil (lambda (element)
(incf (gethash element frequencies 0)))
sequence)
(let ((modes '())
(hifreq 0 ))
(maphash (lambda (element frequency)
(cond ((> frequency hifreq)
(setf hifreq frequency
modes  (list element)))
((= frequency hifreq)
(push element modes))))
frequencies)
(values modes hifreq))))


## D

The mode function returns a range of all the mode items:

import std.stdio, std.algorithm, std.array;

auto mode(T)(T[] items) pure /*nothrow @safe*/ {
int[T] aa;
foreach (item; items)
aa[item]++;
immutable m = aa.byValue.reduce!max;
return aa.byKey.filter!(k => aa[k] == m);
}

void main() /*@safe*/ {
auto data = [1, 2, 3, 1, 2, 4, 2, 5, 3, 3, 1, 3, 6];
writeln("Mode: ", data.mode);

data ~= 2;
writeln("Mode: ", data.mode);
}

Output:
Mode: [3]
Mode: [2, 3]

## Delphi

program AveragesMode;

{$APPTYPE CONSOLE} uses System.SysUtils, System.Generics.Collections, System.Generics.Defaults; type TCounts = TDictionary<Integer, Integer>; TPair = record value, count: Integer; constructor Create(value, count: Integer); end; TPairs = TArray<TPair>; var dict: TCounts; Pairs: TPairs; list: TArray<Integer>; i, key, max: Integer; p: TPair; { TPair } constructor TPair.Create(value, count: Integer); begin self.value := value; self.count := count; end; function SortByCount(const left, right: TPair): Integer; begin Result := right.count - left.count; end; begin list := [1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 12, 12, 17]; dict := TCounts.Create; for i in list do begin if dict.ContainsKey(i) then dict[i] := dict[i] + 1 else begin dict.Add(i, 1); end; end; SetLength(Pairs, dict.Count); i := 0; for key in dict.Keys do begin Pairs[i] := TPair.Create(key, dict[key]); inc(i); end; TArray.Sort<TPair>(Pairs, TComparer<TPair>.Construct(SortByCount)); Writeln('Modes:'); max := Pairs[0].count; for p in Pairs do if p.count = max then Writeln(' Value: ', p.value, ', Count: ', p.count); dict.Free; Readln; end.  Output: Modes: Value: 6, Count: 4 Value: 12, Count: 4 ## E pragma.enable("accumulator") def mode(values) { def counts := [].asMap().diverge() var maxCount := 0 for v in values { maxCount max= (counts[v] := counts.fetch(v, fn{0}) + 1) } return accum [].asSet() for v => ==maxCount in counts { _.with(v) } } ? mode([1,1,2,2,3,3,4,4,4,5,5,6,6,7,8,8,9,9,0,0,0]) # value: [4, 0].asSet() In the line "maxCount max= (counts[v] := counts.fetch(v, fn{0}) + 1)", max= is an update-assignment operation like +=. (The parentheses are unnecessary.) A more verbose version would be:  def newCount := counts.fetch(v, fn { 0 }) + 1 counts[v] := newCount maxCount := maxCount.max(newCount) In for loops, each key and value from the collection are pattern matched against the specified key pattern => value pattern. In "for v => ==maxCount in counts", the == is a pattern-match operator which fails unless the value examined is equal to the specified value; so this selects only the input values (keys in counts) whose counts are equal to the maximum count. ## EasyLang proc modes . in[] r[] . r[] = [ ] for v in in[] for i to len vals[] if v = vals[i] cnt[i] += 1 max = higher cnt[i] max break 1 . . vals[] &= v cnt[] &= 0 . for i to len cnt[] if cnt[i] = max r[] &= vals[i] . . . in[] = [ 1 3 6 6 6 6 7 7 12 12 17 ] modes in[] mods[] print mods[] in[] = [ 1 1 2 4 4 ] modes in[] mods[] print mods[]  ## EchoLisp (define (modes L) (define G (group* L)) ;; sorts and group equal items (define cardmax (for/max [(g G)] (length g))) (map first (filter (lambda(g) (= cardmax (length g))) G))) (modes '( a b c a d e f)) → (a) (modes (iota 6)) → (0 1 2 3 4 5) (modes '(x)) → (x) (modes '(🎾 🏉 ☕️ 🎾 🎲 🎯 🎺 ☕️ 🎲 🎸 🎻 🏆 ☕️ 🏁 🎾 🎲 🎻 🏉 )) → (🎾 ☕️ 🎲) (modes '()) 😖️ error: group : expected list : null 🔎 'modes'  ## Elena ELENA 6.x: import system'routines; import system'collections; import extensions; extension op { get Mode() { var countMap := Dictionary.new(0); self.forEach::(item) { countMap[item] := countMap[item] + 1 }; countMap := countMap.Values.sort::(p,n => p > n); var max := countMap.FirstMember; ^ countMap .filterBy::(kv => max.equal(kv.Value)) .selectBy::(kv => kv.Key) .toArray() } } public program() { var array1 := new int[]{1, 1, 2, 4, 4}; var array2 := new int[]{1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17}; var array3 := new object[]{1, "blue", 2, 7.5r, 5, "green", "red", 5, 2, "blue", "white"}; console .printLine("mode of (",array1.asEnumerable(),") is (",array1.Mode,")") .printLine("mode of (",array2.asEnumerable(),") is (",array2.Mode,")") .printLine("mode of (",array3.asEnumerable(),") is (",array3.Mode,")") .readChar() } Output: mode of (1,1,2,4,4) is (4,1) mode of (1,3,6,6,6,6,7,7,12,12,17) is (6) mode of (1,blue,2,7.5,5,green,red,5,2,blue,white) is (5,2,blue)  ## Elixir defmodule Average do def mode(list) do gb = Enum.group_by(list, &(&1)) max = Enum.map(gb, fn {_,val} -> length(val) end) |> Enum.max for {key,val} <- gb, length(val)==max, do: key end end lists = [[3,1,4,1,5,9,2,6,5,3,5,8,9], [1, 2, "qwe", "asd", 1, 2, "qwe", "asd", 2, "qwe"]] Enum.each(lists, fn list -> IO.puts "mode: #{inspect list}" IO.puts " => #{inspect Average.mode(list)}" end)  Output: mode: [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9] => [5] mode: [1, 2, "qwe", "asd", 1, 2, "qwe", "asd", 2, "qwe"] => [2, "qwe"]  ## Erlang -module( mode ). -export( [example/0, values/1] ). example() -> Set = [1, 2, "qwe", "asd", 1, 2, "qwe", "asd", 2, "qwe"], io:fwrite( "In ~p the mode(s) is(are): ~p~n", [Set, values(Set)] ). values( Set ) -> Dict = lists:foldl( fun values_count/2, dict:new(), Set ), [X || {X, _Y} <- dict:fold( fun keep_maxs/3, [{0, 0}], Dict )]. keep_maxs( Key, Value, [{_Max_key, Max_value} | _] ) when Value > Max_value -> [{Key, Value}]; keep_maxs( Key, Value, [{_Max_key, Max_value} | _]=Maxs ) when Value =:= Max_value -> [{Key, Value} | Maxs]; keep_maxs( _Key, _Value, Maxs ) -> Maxs. values_count( Value, Dict ) -> dict:update_counter( Value, 1, Dict ).  Output: 12> mode:example(). In [1, 2, "qwe", "asd", 1, 2, "qwe", "asd", 2, "qwe"] the mode(s) is(are): ["qwe", 2]  ## ERRE PROGRAM MODE_AVG !$INTEGER

DIM A[10],B[10],Z[10]

PROCEDURE SORT(Z[],P->Z[])
LOCAL N,FLIPS
FLIPS=TRUE
WHILE FLIPS DO
FLIPS=FALSE
FOR N=0 TO P-1 DO
IF Z[N]>Z[N+1] THEN SWAP(Z[N],Z[N+1]) FLIPS=TRUE
END FOR
END WHILE
END PROCEDURE

PROCEDURE CALC_MODE(Z[],P->MODES$) LOCAL I,OCCURRENCE,MAXOCCURRENCE,OLDVAL SORT(Z[],P->Z[]) OCCURENCE=1 MAXOCCURENCE=0 OLDVAL=Z[0] MODES$=""
FOR I=1 TO P DO
IF Z[I]=OLDVAL THEN
OCCURENCE=OCCURENCE+1
ELSE
IF OCCURENCE>MAXOCCURENCE THEN
MAXOCCURENCE=OCCURENCE
MODES$=STR$(OLDVAL)
ELSIF OCCURENCE=MAXOCCURENCE THEN
MODES$=MODES$+STR$(OLDVAL) ELSE !$NULL
END IF
OCCURENCE=1
END IF
OLDVAL=Z[I]
END FOR
!check after loop
IF OCCURENCE>MAXOCCURENCE THEN
MAXOCCURENCE=OCCURENCE
MODES$=STR$(OLDVAL)
ELSIF OCCURENCE=MAXOCCURENCE THEN
MODES$=MODES$+STR$(OLDVAL) ELSE !$NULL
END IF
END PROCEDURE

BEGIN
A[]=(1,3,6,6,6,6,7,7,12,12,17)
B[]=(1,2,4,4,1)
PRINT("Modes for array A (1,3,6,6,6,6,7,7,12,12,17)";)
CALC_MODE(A[],10->MODES$) PRINT(MODES$)
PRINT("Modes for array B (1,2,4,4,1)";)
CALC_MODE(B[],4->MODES$) PRINT(MODES$)
END PROGRAM
Output:
Modes for array A (1,3,6,6,6,6,7,7,12,12,17) 6
Modes for array B (1,2,4,4,1) 1 4


## Euphoria

include misc.e

function mode(sequence s)
sequence uniques, counts, modes
integer j,max
uniques = {}
counts = {}
for i = 1 to length(s) do
j = find(s[i], uniques)
if j then
counts[j] += 1
else
uniques = append(uniques, s[i])
counts  = append(counts, 1)
end if
end for

max = counts[1]
for i = 2 to length(counts) do
if counts[i] > max then
max = counts[i]
end if
end for

j = 1
modes = {}
while j <= length(s) do
j = find_from(max, counts, j)
if j = 0 then
exit
end if
modes = append(modes, uniques[j])
j += 1
end while
return modes
end function

constant s = { 1, "blue", 2, 7.5, 5, "green", "red", 5, 2, "blue", "white" }
pretty_print(1,mode(s),{3})
Output:
{
"blue",
2,
5
}

## F#

The Unchecked.defaultof became available in version 1.9.4 I think.

let mode (l:'a seq) =
l
|> Seq.countBy (fun item -> item)               // Count individual items
|> Seq.fold                                     // Find max counts
(fun (cp, lst) (item, c) ->                 // State is (count, list of items with that count)
if c > cp then (c, [item])              // New max - keep count and a list of the single item
elif c = cp then (c, item :: lst)       // New element with max count - prepend it to the list
else (cp,lst))                          // else just keep old count/list
(0, [Unchecked.defaultof<'a>])              // Start with a count of 0 and a dummy item
|> snd                                          // From (count, list) we just want the second item (the list)


Example usage:

> mode ["a"; "b"; "c"; "c"];;
val it : string list = ["c"]
> mode ["a"; "b"; "c"; "c";"a"];;
val it : string list = ["c"; "a"]
> mode [1;2;1;3;2;0;0];;
val it : int list = [0; 2; 1]


## Factor

Factor has the word mode in math.statistics vocabulary.

{ 11 9 4 9 4 9 } mode ! 9


## Fortran

Works with: Fortran version 90 and later

For the Qsort_Module see Sorting_algorithms/Quicksort#Fortran

program mode_test
use Qsort_Module only Qsort => sort
implicit none

integer, parameter    :: S = 10
integer, dimension(S) :: a1 = (/ -1, 7, 7, 2, 2, 2, -1, 7, -3, -3 /)
integer, dimension(S) :: a2 = (/  1, 1, 1, 1, 1, 0, 2, 2, 2, 2 /)
integer, dimension(S) :: a3 = (/  0, 0, -1, -1, 9, 9, 3, 3, 7, 7 /)

integer, dimension(S) :: o
integer               :: l, trash

print *, stat_mode(a1)

trash = stat_mode(a1, o, l)
print *, o(1:l)
trash = stat_mode(a2, o, l)
print *, o(1:l)
trash = stat_mode(a3, o, l)
print *, o(1:l)

contains

! stat_mode returns the lowest (if not unique) mode
! others can hold other modes, if the mode is not unique
! if others is provided, otherslen should be provided too, and
! it says how many other modes are there.
! ok can be used to know if the return value has a meaning
! or the mode can't be found (void arrays)
integer function stat_mode(a, others, otherslen, ok)
integer, dimension(:), intent(in) :: a
logical, optional, intent(out)    :: ok
integer, dimension(size(a,1)), optional, intent(out) :: others
integer, optional, intent(out)    :: otherslen

! ta is a copy of a, we sort ta modifying it, freq
! holds the frequencies and idx the index (for ta) so that
! the value appearing freq(i)-time is ta(idx(i))
integer, dimension(size(a, 1)) :: ta, freq, idx
integer                        :: rs, i, tm, ml, tf

if ( present(ok) ) ok = .false.

select case ( size(a, 1) )
case (0)  ! no mode... ok is false
return
case (1)
if ( present(ok) ) ok = .true.
stat_mode = a(1)
return
case default
if ( present(ok) ) ok = .true.
ta = a         ! copy the array
call sort(ta)  ! sort it in place (cfr. sort algos on RC)
freq = 1
idx = 0
rs = 1         ! rs will be the number of different values

do i = 2, size(ta, 1)
if ( ta(i-1) == ta(i) ) then
freq(rs) = freq(rs) + 1
else
idx(rs) = i-1
rs = rs + 1
end if
end do
idx(rs) = i-1

ml = maxloc(freq(1:rs), 1)  ! index of the max value of freq
tf = freq(ml)               ! the max frequency
tm = ta(idx(ml))            ! the value with that freq

! if we want all the possible modes, we provide others
if ( present(others) ) then
i = 1
others(1) = tm
do
freq(ml) = 0
ml = maxloc(freq(1:rs), 1)
if ( tf == freq(ml) ) then ! the same freq
i = i + 1               ! as the max one
others(i) = ta(idx(ml))
else
exit
end if
end do

if ( present(otherslen) ) then
otherslen = i
end if

end if
stat_mode = tm
end select

end function stat_mode

end program mode_test


## FreeBASIC

' FB 1.05.0 Win64

Sub quicksort(a() As Integer, first As Integer, last As Integer)
Dim As Integer length = last - first + 1
If length < 2 Then Return
Dim pivot As Integer = a(first + length\ 2)
Dim lft As Integer = first
Dim rgt As Integer = last
While lft <= rgt
While a(lft) < pivot
lft +=1
Wend
While a(rgt) > pivot
rgt -= 1
Wend
If lft <= rgt Then
Swap a(lft), a(rgt)
lft += 1
rgt -= 1
End If
Wend
quicksort(a(), first, rgt)
quicksort(a(), lft, last)
End Sub

' The modal value(s) is/are stored in 'm'.
' The function returns the modal count.
Function mode(a() As Integer, m() As Integer, sorted As Boolean = false) As Integer
Dim lb As Integer = LBound(a)
Dim ub As Integer = UBound(a)
If ub = -1 Then Return 0 '' empty array
If Not sorted Then quicksort(a(), lb, ub)
Dim cValue As Integer = a(lb)
Dim cCount As Integer = 1
Dim cMax As Integer = 0
'' We iterate to the end of the array plus 1 to ensure the
'' final value is dealt with properly
For i As Integer = lb + 1 To ub + 1
If i <= ub AndAlso a(i) = cValue Then
cCount += 1
Else
If cCount > cMax Then
Erase m
Redim m(1 To 1)
m(1) = cValue
cMax = cCount
ElseIf cCount = cMax Then
Redim Preserve m(1 To UBound(m) + 1)
m(UBound(m)) = cValue
End If
If i = ub + 1 Then Exit For
cValue = a(i)
cCount = 1
End If
Next
Return cMax
End Function

Dim a(1 To 14) As Integer  = {1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6}
Dim m() As Integer '' to store the mode(s)
Dim mCount As Integer = mode(a(), m())
Print "The following are the modes which occur"; mCount; " times : "
For i As Integer = LBound(m) To UBound(m) : Print m(i); " "; : Next
Print
Print "Press any key to quit"
Sleep

Output:
c:\FreeBasic>mode
The following are the modes which occur 4 times :
2  3


## Frink

modes[vals] :=
{
count = countToArray[vals]
biggest = count@0@1
result = new array

for i = rangeOf[count]
if count@i@1 < biggest
break  // count is sorted so we can bail out when numbers decrease
else
result.push[count@i@0]

return result
}

println[modes[[1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]]]
println[modes[[1, 1, 2, 4, 4]]]
Output:
[6]
[1, 4]


As of the 2022-07-31 release of Frink, the function can be rewritten as:

modes[vals] := mostCommon[vals]@0

## FutureBasic

FB has a native function for an array of mode averages.

local fn ModeAverage( arguments as CFArrayRef ) as CFStringRef
ExpressionRef  expRef = fn ExpressionForFunction( @"mode:", @[fn ExpressionForConstantValue( arguments )] )
CFArrayRef  modeArray = fn ExpressionValueWithObject( expRef, NULL, NULL )
CFNumberRef    number
CFMutableStringRef modeStr = fn MutableStringNew
for number in modeArray
MutableStringAppendFormat( modeStr, @"value = %@\n", number )
next
end fn = modeStr

print fn ModeAverage( @[@1, @3, @6, @6, @6, @6, @7, @7, @12, @12, @12, @12, @17] )

HandleEvents
Output:
value = 6
value = 12


## GAP

mode := function(v)
local c, m;
c := Collected(SortedList(v));
m := Maximum(List(c, x -> x[2]));
return List(Filtered(c, x -> x[2] = m), y -> y[1]);
end;

mode([ 7, 5, 6, 1, 5, 5, 7, 12, 17, 6, 6, 5, 12, 3, 6 ]);
# [ 5, 6 ]


## Go

Fixed collection type, fixed value type. In Go it is appropriate to program directly with built in types when possible.

package main

import "fmt"

func main() {
fmt.Println(mode([]int{2, 7, 1, 8, 2}))
fmt.Println(mode([]int{2, 7, 1, 8, 2, 8}))
}

func mode(a []int) []int {
m := make(map[int]int)
for _, v := range a {
m[v]++
}
var mode []int
var n int
for k, v := range m {
switch {
case v < n:
case v > n:
n = v
mode = append(mode[:0], k)
default:
mode = append(mode, k)
}
}
return mode
}

Output:
[2]
[2 8]


Fixed collection type, unspecified value type. An empty interface can hold any type. A slice []interface can hold a mix of types. It's not too much more source code, although there is some overhead to support this generality.

package main

import "fmt"

func main() {
fmt.Println(mode([]interface{}{.2, .7, .1, .8, .2}))
fmt.Println(mode([]interface{}{"two", 7, 1, 8, "two", 8}))
}

func mode(a []interface{}) []interface{} {
m := make(map[interface{}]int)
for _, v := range a {
m[v]++
}
var mode []interface{}
var n int
for k, v := range m {
switch {
case v < n:
case v > n:
n = v
mode = append(mode[:0], k)
default:
mode = append(mode, k)
}
}
return mode
}

Output:
[0.2]
[two 8]


General collection, fixed value type. The other kind of generality mentioned in the task requires more code. In Go this is done with an interface to define generalized collection methods. Here, the only method we need to demonstrate is iteration over the collection, so the interface has only one method. Any number of types then can implement the interface. Note that the mode function now takes an object of this interface type. In effect, it becomes a generic function, oblivious to the implementation of the collection, and accessing it only through its methods.

package main

import "fmt"

// interface type
type intCollection interface {
iterator() func() (int, bool)
}

// concrete type implements interface
type intSlice []int

// method on concrete type satisfies interface method
func (s intSlice) iterator() func() (int, bool) {
i := 0
return func() (int, bool) {
if i >= len(s) {
return 0, false
}
v := s[i]
i++
return v, true
}
}

func main() {
fmt.Println(mode(intSlice{2, 7, 1, 8, 2}))
fmt.Println(mode(intSlice{2, 7, 1, 8, 2, 8}))
}

// mode is now a generic function, in a sense.
// It knows what to do with an intCollection,
// but does not know the underlying concrete type.
func mode(a intCollection) []int {
m := make(map[int]int)
i := a.iterator()
for {
v, ok := i()
if !ok {
break
}
m[v]++
}
var mode []int
var n int
for k, v := range m {
switch {
case v < n:
case v > n:
n = v
mode = append(mode[:0], k)
default:
mode = append(mode, k)
}
}
return mode
}

Output:
[2]
[8 2]


General collection, unspecified value type, Finally, the two kinds of generality can be combined. The iterator returned by the interface method now returns an empty interface rather than an int. The intSlice concrete type of the previous example is retained, but now it must satisfy this interface method that uses interface{} instead of int. runeList is added to illustrate how multiple types can satisfy the same interface.

package main

import "fmt"

type collection interface {
iterator() func() (interface{}, bool)
}

type intSlice []int

func (s intSlice) iterator() func() (interface{}, bool) {
i := 0
return func() (interface{}, bool) {
if i >= len(s) {
return 0, false
}
v := s[i]
i++
return v, true
}
}

type runeList string

func (s runeList) iterator() func() (interface{}, bool) {
c := make(chan rune)
go func() {
for _, r := range s {
c <- r
}
close(c)
}()
return func() (interface{}, bool) {
r, ok := <-c
return string(r), ok
}
}

func main() {
fmt.Println(mode(intSlice{2, 7, 1, 8, 2}))
fmt.Println(mode(runeList("Enzyklopädie")))
}

func mode(a collection) []interface{} {
m := make(map[interface{}]int)
i := a.iterator()
for {
v, ok := i()
if !ok {
break
}
m[v]++
}
var mode []interface{}
var n int
for k, v := range m {
switch {
case v < n:
case v > n:
n = v
mode = append(mode[:0], k)
default:
mode = append(mode, k)
}
}
return mode
}

Output:

("Enzyklopädie" has no repeated letters. All are modal.)

[2]
[e d i k l o n p y z E ä]


## Groovy

Solution, both "collection type" and "element type" agnostic:

def mode(Iterable col) {
assert col
def m = [:]
col.each {
m[it] = m[it] == null ? 1 : m[it] + 1
}
def keys = m.keySet().sort { -m[it] }
keys.findAll { m[it] == m[keys[0]] }
}


Test:

def random = new Random()
def sourceList = [ 'Lamp', 42.0, java.awt.Color.RED, new Date(), ~/pattern/]
(0..10).each {
def a = (0..10).collect { sourceList[random.nextInt(5)] }
println "${mode(a)} == mode(${a})"
}

Output:
[pattern]    ==    mode([pattern, pattern, pattern, Lamp, pattern, Fri Oct 28 23:43:20 CDT 2011, java.awt.Color[r=255,g=0,b=0], Lamp, Lamp, Lamp, pattern])
[Lamp]    ==    mode([Lamp, Fri Oct 28 23:43:20 CDT 2011, Lamp, java.awt.Color[r=255,g=0,b=0], 42.0, java.awt.Color[r=255,g=0,b=0], Fri Oct 28 23:43:20 CDT 2011, Lamp, pattern, pattern, 42.0])
[java.awt.Color[r=255,g=0,b=0]]    ==    mode([java.awt.Color[r=255,g=0,b=0], java.awt.Color[r=255,g=0,b=0], 42.0, 42.0, Fri Oct 28 23:43:20 CDT 2011, Fri Oct 28 23:43:20 CDT 2011, 42.0, java.awt.Color[r=255,g=0,b=0], pattern, pattern, java.awt.Color[r=255,g=0,b=0]])
[Fri Oct 28 23:43:20 CDT 2011]    ==    mode([Fri Oct 28 23:43:20 CDT 2011, pattern, 42.0, Fri Oct 28 23:43:20 CDT 2011, Lamp, pattern, Fri Oct 28 23:43:20 CDT 2011, java.awt.Color[r=255,g=0,b=0], 42.0, 42.0, Fri Oct 28 23:43:20 CDT 2011])
[Fri Oct 28 23:43:20 CDT 2011, Lamp]    ==    mode([42.0, Fri Oct 28 23:43:20 CDT 2011, Lamp, Lamp, Fri Oct 28 23:43:20 CDT 2011, Fri Oct 28 23:43:20 CDT 2011, 42.0, Lamp, java.awt.Color[r=255,g=0,b=0], Lamp, Fri Oct 28 23:43:20 CDT 2011])
[java.awt.Color[r=255,g=0,b=0]]    ==    mode([Fri Oct 28 23:43:20 CDT 2011, java.awt.Color[r=255,g=0,b=0], java.awt.Color[r=255,g=0,b=0], pattern, 42.0, java.awt.Color[r=255,g=0,b=0], java.awt.Color[r=255,g=0,b=0], 42.0, pattern, Fri Oct 28 23:43:20 CDT 2011, pattern])
[42.0, java.awt.Color[r=255,g=0,b=0]]    ==    mode([42.0, java.awt.Color[r=255,g=0,b=0], pattern, Fri Oct 28 23:43:20 CDT 2011, Lamp, java.awt.Color[r=255,g=0,b=0], Lamp, Fri Oct 28 23:43:20 CDT 2011, java.awt.Color[r=255,g=0,b=0], 42.0, 42.0])
[Fri Oct 28 23:43:20 CDT 2011]    ==    mode([java.awt.Color[r=255,g=0,b=0], pattern, Fri Oct 28 23:43:20 CDT 2011, Lamp, 42.0, Fri Oct 28 23:43:20 CDT 2011, Fri Oct 28 23:43:20 CDT 2011, pattern, java.awt.Color[r=255,g=0,b=0], Lamp, Fri Oct 28 23:43:20 CDT 2011])
[Fri Oct 28 23:43:20 CDT 2011]    ==    mode([Fri Oct 28 23:43:20 CDT 2011, pattern, Fri Oct 28 23:43:20 CDT 2011, java.awt.Color[r=255,g=0,b=0], pattern, Fri Oct 28 23:43:20 CDT 2011, 42.0, java.awt.Color[r=255,g=0,b=0], Lamp, Fri Oct 28 23:43:20 CDT 2011, 42.0])
[pattern]    ==    mode([42.0, pattern, pattern, Lamp, 42.0, Lamp, Fri Oct 28 23:43:20 CDT 2011, java.awt.Color[r=255,g=0,b=0], pattern, 42.0, pattern])
[Lamp, 42.0]    ==    mode([Fri Oct 28 23:43:20 CDT 2011, pattern, Lamp, Lamp, Lamp, java.awt.Color[r=255,g=0,b=0], Fri Oct 28 23:43:20 CDT 2011, 42.0, 42.0, pattern, 42.0])

import Prelude (foldr, maximum, (==), (+))
import Data.Map (insertWith', empty, filter, elems, keys)

mode :: (Ord a) => [a] -> [a]
mode xs = keys (filter (== maximum (elems counts)) counts)
where counts = foldr (\x -> insertWith' (+) x 1) empty xs


counts is a map from each value found in xs to the number of occurrences (foldr traverses the list, insertWith' increments the count). This map is then filtered to only those entries whose count is the maximum count, and their keys (the values from the input list) are returned.

> mode [1,2,3,3,2,1,1]
[1]
> mode [1,2,3,3,2,1]
[1,2,3]


Alternately:

import Data.List (group, sort)

mode :: (Ord a) => [a] -> [a]
mode xs = map fst $filter ((==best).snd) counts where counts = map (\l -> (head l, length l)) . group . sort$ xs
best = maximum (map snd counts)


Another version that does not require an orderable type:

import Data.List (partition)

mode :: (Eq a) => [a] -> [a]
mode = snd . modesWithCount
where modesWithCount :: (Eq a) => [a] -> (Int, [a])
modesWithCount [] = (0,[])
modesWithCount l@(x:_) | length xs > best = (length xs, [x])
| length xs < best = (best, modes)
| otherwise        = (best, x:modes)
where (xs, notxs) = partition (== x) l
(best, modes) = modesWithCount notxs


## Icon and Unicon

The mode procedure generates all n mode values if the collection is n-modal.

procedure main(args)
every write(!mode(args))
end

procedure mode(A)
hist := table(0)
every hist[!A] +:= 1
hist := sort(hist, 2)
modeCnt := hist[*hist][2]
every modeP := hist[*hist to 1 by -1] do {
if modeCnt = modeP[2] then suspend modeP[1]
else fail
}
end

Sample outputs:
->am 3 1 4 1 5 9 7 6
1
->am 3 1 4 1 5 9 7 6 3
3
1
->

## J

mode=: ~. #~ ( = >./ )@( #/.~ )


Literally: select from the unique values the values which appear the most often.

Example:

   mode 1 1 2 2 3 3 4 4 4 5 5 6 6 7 8 8 9 9 0 0 0
4 0
mode 1 3 6 6 6 6 7 7 12 12 17
6
mode 1 2 4 4 1
1 4


## Jakt

An empty set is returned if the iterable is empty.

fn mode<T, U>(anon iterable: U) throws -> {T} {
mut dictionary = Dictionary<T, u64>()
for item in iterable {
if dictionary.contains(item) {
dictionary[item]++
} else {
dictionary[item] = 1
}
}

mut items = dictionary.iterator()

let mode = items.next()
if not mode.has_value() {
let empty_set: {T} = {}
return empty_set
}

mut modes = [mode.value()]
for item in items {
if item.1 > modes[0].1 {
modes = [item]
} else if item.1 == modes[0].1 {
modes.push(item)
}
}

mut mode_set: {T} = {}
for mode in modes {
}

return mode_set
}

fn main() {
println("{}", mode<i64>([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]))
println("{}", mode<i64>([1, 1, 2, 4, 4]))

let empty_array: [i64] = []
println("{}", mode<i64>(empty_array))

let test_string = "abcabbcaca"
println("{}", mode<u32>(test_string.code_points()))
}

## Java

import java.util.*;

public class Mode {
public static <T> List<T> mode(List<? extends T> coll) {
Map<T, Integer> seen = new HashMap<T, Integer>();
int max = 0;
List<T> maxElems = new ArrayList<T>();
for (T value : coll) {
if (seen.containsKey(value))
seen.put(value, seen.get(value) + 1);
else
seen.put(value, 1);
if (seen.get(value) > max) {
max = seen.get(value);
maxElems.clear();
} else if (seen.get(value) == max) {
}
}
return maxElems;
}

public static void main(String[] args) {
System.out.println(mode(Arrays.asList(1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17))); // prints [6]
System.out.println(mode(Arrays.asList(1, 1, 2, 4, 4))); // prints [1, 4]
}
}


## JavaScript

function mode(ary) {
var counter = {};
var mode = [];
var max = 0;
for (var i in ary) {
if (!(ary[i] in counter))
counter[ary[i]] = 0;
counter[ary[i]]++;

if (counter[ary[i]] == max)
mode.push(ary[i]);
else if (counter[ary[i]] > max) {
max = counter[ary[i]];
mode = [ary[i]];
}
}
return mode;
}

mode([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]);  // [6]
mode([1, 2, 4, 4, 1]);  // [1,4]


## jq

jq only supports hashing of strings, so to preserve generality -- that is, to avoid assuming anything about the input array -- we simply sort it.

jq's sort is very fast in any case.

# modes/0 produces an array of [value, count]
# in increasing order of count:
def modes:
sort | reduce .[] as $i ([]; # state variable is an array of [value, count] if length == 0 then [ [$i, 1] ]
elif .[-1][0] == $i then setpath([-1,1]; .[-1][1] + 1) else . + [[$i,1]]
end )
| sort_by( .[1] );

# mode/0 outputs a stream of the modal values;
# if the input array is empty, the output stream is also empty.
def mode:
if length == 0 then empty
else modes as $modes |$modes[-1][1] as $count |$modes[] | select( .[1] == $count) | .[0] end; Examples: [1,2,3,1,2,1] | mode # => 1 [1,2,3,1,2,1,2] | mode # => 1 2 [1.1, 1.2, 1.3, 1.1, 1.2, 1.1] | mode) # => 1.1 ## Julia function modes(values) dict = Dict() # Values => Number of repetitions modesArray = typeof(values[1])[] # Array of the modes so far max = 0 # Max of repetitions so far for v in values # Add one to the dict[v] entry (create one if none) if v in keys(dict) dict[v] += 1 else dict[v] = 1 end # Update modesArray if the number of repetitions # of v reaches or surpasses the max value if dict[v] >= max if dict[v] > max empty!(modesArray) max += 1 end append!(modesArray, [v]) end end return modesArray end println(modes([1,3,6,6,6,6,7,7,12,12,17])) println(modes((1,1,2,4,4)))  ## K  mode: {(?x)@&n=|/n:#:'=x} mode 1 1 1 1 2 2 2 3 3 3 3 4 4 3 2 4 4 4 3 4  ## Kotlin fun <T> modeOf(a: Array<T>) { val sortedByFreq = a.groupBy { it }.entries.sortedByDescending { it.value.size } val maxFreq = sortedByFreq.first().value.size val modes = sortedByFreq.takeWhile { it.value.size == maxFreq } if (modes.size == 1) println("The mode of the collection is${modes.first().key} which has a frequency of $maxFreq") else { print("There are${modes.size} modes with a frequency of $maxFreq, namely : ") println(modes.map { it.key }.joinToString(", ")) } } fun main(args: Array<String>) { val a = arrayOf(7, 1, 1, 6, 2, 4, 2, 4, 2, 1, 5) println("[" + a.joinToString(", ") + "]") modeOf(a) println() val b = arrayOf(true, false, true, false, true, true) println("[" + b.joinToString(", ") + "]") modeOf(b) }  Output: [7, 1, 1, 6, 2, 4, 2, 4, 2, 1, 5] There are 2 modes with a frequency of 3, namely : 1, 2 [true, false, true, false, true, true] The mode of the collection is true which has a frequency of 4  ## Lasso define getmode(a::array)::array => { local(mmap = map, maxv = 0, modes = array) // store counts with e in #a do => { #mmap->keys >> #e ? #mmap->find(#e) += 1 | #mmap->insert(#e = 1) } // get max value with e in #mmap->keys do => { #mmap->find(#e) > #maxv ? #maxv = #mmap->find(#e) } // get modes with max value with e in #mmap->keys where #mmap->find(#e) == #maxv do => { #modes->insert(#e) } return #modes } getmode(array(1,3,6,6,6,6,7,7,12,12,17)) getmode(array(1,3,6,3,4,8,9,1,2,3,2,2))  Output: array(6) array(2, 3) ## Liberty BASIC Using string of integers instead collection. a$ = "1 3 6 6 6 6 7 7 12 12 17"
b$= "1 2 4 4 1" print "Modes for ";a$
print modes$(a$)
print "Modes for ";b$print modes$(b$) function modes$(a$) 'get array size n=0 t$ = "*"
while t$<>"" n=n+1 t$=word$(a$, n)
'print n, t$wend n=n-1 'print "n=", n 'dim array 'read in array redim a(n) for i = 1 to n a(i)=val(word$(a$, i)) 'print i, a(i) next 'sort sort a(), 1, n 'get the modes occurence = 1 maxOccurence = 0 oldVal = a(1) modes$ = ""
for i = 2 to n
'print i, a(i)
if a(i) = oldVal then
occurence = occurence + 1
else
select case
case occurence >  maxOccurence
maxOccurence = occurence
modes$= oldVal; " " case occurence = maxOccurence modes$ =  modes$; oldVal; " " end select occurence = 1 end if oldVal = a(i) next 'check after loop select case case occurence > maxOccurence maxOccurence = occurence modes$ = oldVal; " "
case occurence = maxOccurence
modes$= modes$; oldVal; " "
end select
end function
Output:
Modes for 1 3 6 6 6 6 7 7 12 12 17
6
Modes for 1 2 4 4 1
1 4


## Lua

function mode(tbl) -- returns table of modes and count
assert(type(tbl) == 'table')
local counts = { }
for _, val in pairs(tbl) do
-- see http://lua-users.org/wiki/TernaryOperator
counts[val] = counts[val] and counts[val] + 1 or 1
end
local modes = { }
local modeCount = 0
for key, val in pairs(counts) do
if val > modeCount then
modeCount = val
modes = {key}
elseif val == modeCount then
table.insert(modes, key)
end
end
return modes, modeCount
end

modes, count = mode({1,3,6,6,6,6,7,7,12,12,17})
for _, val in pairs(modes) do io.write(val..' ') end
print("occur(s) ", count, " times")

modes, count = mode({'a', 'a', 'b', 'd', 'd'})
for _, val in pairs(modes) do io.write(val..' ') end
print("occur(s) ", count, " times")


## M2000 Interpreter

We use Inventory with keys as numbers (internal are strings). Inventories work with hash function. So searching is very fast.

Function return an inventory, with all "modes" with same max number. Now work with mix numbers and strings. Islet return true if top of stack is letter (string).

Module Checkit {
\\ find mode
Function GetMode {
Inventory  N
Inventory ALLMODES
m=1
While not empty {
if islet then  {
Read A$if Exist(N, A$) then  {
k=Eval(N)
k++
if m=k then  {
Append ALLMODES, A$} if m<k then m=k : Clear ALLMODES : Append ALLMODES, A$
return N, A$:=k } Else Append N, A$:=1 : if m=1 then Append ALLMODES, A$} else { Read A if Exist(N, A) then { k=Eval(N) k++ if m=k then { Append ALLMODES, A } if m<k then m=k : Clear ALLMODES : Append ALLMODES, A return N, A:=k } Else Append N, A:=1 : if m=1 then Append ALLMODES, A } } =ALLMODES } Print GetMode(1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6) ' print 2 3 Dim A() A()=(1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6) \\ get a pointer from A m=A() Print GetMode(!m) ' print 2 3 z=stack:=1, 2,"B", 3, 1, 2, "B", 4, 2, 5,"B", 2, 3, 3, 1, 3, 6, "B" Print GetMode(!z) ' print 2 3 B } Checkit Using idea from BBC BASIC. Function GetMode return array. As Array get bigger function run slower exponential. Previous example using inventory, has linear response (double data, double time to run). Eacb function has a mew stack of value. This one line function Def AllStack()=[] get all arguments and place them in a stack object, and a pointer to stack returned. This function return an array: Def AllArray=Array([]). We can use (,) for empty array, (1,) for one item array, (1,2,3) for three item. We can use ((1,2),(3,4)) for an array with two arrays as items. We can use Stack for empty stack, or Stack:=1,2,3 for a stack with 3 items. Stacks are linked lists. A=Stack : Stack A { push 1,2,3 } : Print A ' print 3 2 1 where 3 is the top. Stack A (Data 0} : Print A ' print 3 2 1 0 (data push to bottom to stack). Functions and Modules always have a "current stack". So M2000 is like basic but is a stack oriented language, but for expressions use infix notation. Module Checkit { Function GetMode(&a()){ Local max% if len(a())=0 then =(,) link a() to a$()
n%=len(a())
dim c%(n%)
if type$(a(0))="String" then { For i%=0 to n%-2 For j%=i%+1 to n%-1 if order(a$(i%), a$(j%))=0 then c%(i%)++ Next j% If c%(i%)>max% Then max%=c%(i%) Next i% For i%=0 to n%-1 If c%(i%) = max% Then Data a$(i%)
Next i%
} Else {
For i%=0 to n%-2
For j%=i%+1 to n%-1
if a(i%)==a(j%) then c%(i%)++
Next j%
If c%(i%)>max% Then max%=c%(i%)
Next i%
For i%=0 to n%-1
If c%(i%) = max% Then Data a(i%)
Next i%
}
=Array([])
}
Dim m()
m()=(2,3,43,234,234,3,324)
Print GetMode(&m())  ' 3 234
k=(1,2,1,2,1,2,3)
n=GetMode(&k)

' iterate backward
i=each(n, -1, 1)
While i {
Print Array(i),
}
Print
k=("A","B","A","B", "B","C","D","A")
? GetMode(&k)    ' A B
}
Checkit

## Maple

The built-in function Statistics:-Mode can be used to compute a mode. When the mode is unique, it returns a numeric result and when there are multiple modes, it returns a set, as in the following example:

Statistics:-Mode([1, 2.1, 2.1, 3]);
Statistics:-Mode([1, 2.1, 2.1, 3.2, 3.2, 5]);
Output:
 2.1
{2.1, 3.2}


## Mathematica / Wolfram Language

Built-in function commonest returns a list of the most common element(s), even is there is only one 'commonest' number. Example for multiple 'commonest' numbers and a single 'commonest' number:

 Commonest[{b, a, c, 2, a, b, 1, 2, 3}]
Commonest[{1, 3, 2, 3}]

Output:
 {b,a,2}
{3}

## MATLAB

function modeValue = findmode(setOfValues)
modeValue = mode(setOfValues);
end


## MUMPS

MODE(X)
;X is assumed to be a list of numbers separated by "^"
;I is a loop index
;L is the length of X
;Y is a new array
;ML is the list of modes
;LOC is a placeholder to shorten the statement
Q:'$DATA(X) "No data" Q:X="" "Empty Set" NEW Y,I,L,LOC SET L=$LENGTH(X,"^"),ML=""
FOR I=1:1:L SET LOC=+$P(X,"^",I),Y(LOC)=$S($DATA(Y(LOC)):Y(LOC)+1,1:1) SET I="",I=$O(Y(I)),ML=I ;Prime the pump, rather than test for no data
FOR  S I=$O(Y(I)) Q:I="" S ML=$SELECT(Y($P(ML,"^"))>Y(I):ML,Y($P(ML,"^"))<Y(I):I,Y($P(ML,"^"))=Y(I):ML_"^"_I) QUIT ML USER>W $$MODE^ROSETTA("1^2^3^2") 2 USER>W$$MODE^ROSETTA("1^2^3^2^3") 2^3 USER>W$$MODE^ROSETTA("") Empty Set ## NetRexx /* NetRexx */ options replace format comments java crossref symbols nobinary run_samples() return -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method mode(lvector = java.util.List) public static returns java.util.List seen = 0 modes = '' modeMax = 0 loop v_ = 0 to lvector.size() - 1 mv = Rexx lvector.get(v_) seen[mv] = seen[mv] + 1 select when seen[mv] > modeMax then do modeMax = seen[mv] modes = '' nx = 1 modes[0] = nx modes[nx] = mv end when seen[mv] = modeMax then do nx = modes[0] + 1 modes[0] = nx modes[nx] = mv end otherwise do nop end end end v_ modeList = ArrayList(modes[0]) loop v_ = 1 to modes[0] val = modes[v_] modeList.add(val) end v_ return modeList -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method mode(rvector = Rexx[]) public static returns java.util.List return mode(ArrayList(Arrays.asList(rvector))) -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method show_mode(lvector = java.util.List) public static returns java.util.List modes = mode(lvector) say 'Vector:' (Rexx lvector).space(0)', Mode(s):' (Rexx modes).space(0) return modes -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method show_mode(rvector = Rexx[]) public static returns java.util.List return show_mode(ArrayList(Arrays.asList(rvector))) -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method run_samples() public static show_mode([Rexx 10, 9, 8, 7, 6, 5, 4, 3, 2, 1]) -- 10 9 8 7 6 5 4 3 2 1 show_mode([Rexx 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0, 0.11]) -- 0 show_mode([Rexx 30, 10, 20, 30, 40, 50, -100, 4.7, -11e+2]) -- 30 show_mode([Rexx 30, 10, 20, 30, 40, 50, -100, 4.7, -11e+2, -11e+2]) -- 30 -11e2 show_mode([Rexx 1, 8, 6, 0, 1, 9, 4, 6, 1, 9, 9, 9]) -- 9 show_mode([Rexx 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]) -- 1 2 3 4 5 6 7 8 9 10 11 show_mode([Rexx 8, 8, 8, 2, 2, 2]) -- 8 2 show_mode([Rexx 'cat', 'kat', 'Cat', 'emu', 'emu', 'Kat']) -- emu show_mode([Rexx 0, 1, 2, 3, 3, 3, 4, 4, 4, 4, 1, 0]) -- 4 show_mode([Rexx 2, 7, 1, 8, 2]) -- 2 show_mode([Rexx 2, 7, 1, 8, 2, 8]) -- 8 2 show_mode([Rexx 'E', 'n', 'z', 'y', 'k', 'l', 'o', 'p', 'ä', 'd', 'i', 'e']) -- E n z y k l o p ä d i e show_mode([Rexx 'E', 'n', 'z', 'y', 'k', 'l', 'o', 'p', 'ä', 'd', 'i', 'e', 'ä']) -- ä show_mode([Rexx 3, 1, 4, 1, 5, 9, 7, 6]) -- 1 show_mode([Rexx 3, 1, 4, 1, 5, 9, 7, 6, 3]) -- 3, 1 show_mode([Rexx 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]) -- 6 show_mode([Rexx 1, 1, 2, 4, 4]) -- 4 1 return  Output: Vector: [10,9,8,7,6,5,4,3,2,1], Mode(s): [10,9,8,7,6,5,4,3,2,1] Vector: [10,9,8,7,6,5,4,3,2,1,0,0,0,0,0.11], Mode(s): [0] Vector: [30,10,20,30,40,50,-100,4.7,-1100], Mode(s): [30] Vector: [30,10,20,30,40,50,-100,4.7,-1100,-1100], Mode(s): [30,-1100] Vector: [1,8,6,0,1,9,4,6,1,9,9,9], Mode(s): [9] Vector: [1,2,3,4,5,6,7,8,9,10,11], Mode(s): [1,2,3,4,5,6,7,8,9,10,11] Vector: [8,8,8,2,2,2], Mode(s): [8,2] Vector: [cat,kat,Cat,emu,emu,Kat], Mode(s): [emu] Vector: [0,1,2,3,3,3,4,4,4,4,1,0], Mode(s): [4] Vector: [2,7,1,8,2], Mode(s): [2] Vector: [2,7,1,8,2,8], Mode(s): [2,8] Vector: [E,n,z,y,k,l,o,p,ä,d,i,e], Mode(s): [E,n,z,y,k,l,o,p,ä,d,i,e] Vector: [E,n,z,y,k,l,o,p,ä,d,i,e,ä], Mode(s): [ä] Vector: [3,1,4,1,5,9,7,6], Mode(s): [1] Vector: [3,1,4,1,5,9,7,6,3], Mode(s): [1,3] Vector: [1,3,6,6,6,6,7,7,12,12,17], Mode(s): [6] Vector: [1,1,2,4,4], Mode(s): [1,4]  ## Nim import tables proc modes[T](xs: openArray[T]): T = var count = initCountTable[T]() for x in xs: count.inc(x) largest(count).key echo modes(@[1,3,6,6,6,6,7,7,12,12,17]) echo modes(@[1,1,2,4,4])  Output: 6 1 ## Oberon-2 Works with: oo2c version2 MODULE Mode; IMPORT Object:Boxed, ADT:Dictionary, ADT:LinkedList, Out := NPCT:Console; TYPE Key = Boxed.LongInt; Val = Boxed.LongInt; VAR x: ARRAY 11 OF LONGINT; y: ARRAY 5 OF LONGINT; z: ARRAY 8 OF LONGINT; PROCEDURE Show(ll: LinkedList.LinkedList(Key)); VAR iter: LinkedList.Iterator(Key); i: LONGINT; k: Key; BEGIN iter := ll.GetIterator(NIL); FOR i := 0 TO ll.Size() - 1 DO; k := iter.Next(); Out.Int(k.value,0);Out.Ln; END; END Show; PROCEDURE Mode(x: ARRAY OF LONGINT): LinkedList.LinkedList(Key); VAR d: Dictionary.Dictionary(Key,Val); i: LONGINT; k: Key; v: Val; iter: Dictionary.IterKeys(Key,Val); resp: LinkedList.LinkedList(Key); max: Boxed.LongInt; BEGIN d := NEW(Dictionary.Dictionary(Key,Val)); FOR i := 0 TO LEN(x) - 1 DO k := NEW(Key,x[i]); IF d.Lookup(k,v) THEN d.Set(k,NEW(Val,v.value + 1)); ELSE d.Set(k,NEW(Val,1)) END END; max := NEW(Boxed.LongInt,0); resp := NEW(LinkedList.LinkedList(Key)); iter := d.IterKeys(); WHILE (iter.Next(k)) DO v := d.Get(k); IF v.Cmp(max) > 0 THEN resp.Clear(); resp.Append(k);max := v ELSIF v.Cmp(max) = 0 THEN resp.Append(k);max := v END END; RETURN resp END Mode; BEGIN x[0] := 1; x[1] := 3; x[2] := 6; x[3] := 6; x[4] := 6; x[5] := 6; x[6] := 7; x[7] := 7; x[8] := 12; x[9] := 12; x[10] := 17; Show(Mode(x));Out.Ln; y[0] := 1; y[1] := 2; y[2] := 4; y[3] := 4; y[4] := 1; Show(Mode(y));Out.Ln; z[0] := 1; z[1] := 2; z[2] := 4; z[3] := 4; z[4] := 1; z[5] := 5; z[6] := 5; z[7] := 5; Show(Mode(z));Out.Ln; END Mode.  {{out} 6 4 1 5  ## Objeck ﻿use Collection; class Mode { function : Main(args : String[]) ~ Nil { Print(Mode([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17])); Print(Mode([1, 2, 4, 4, 1])); } function : Mode(coll : Int[]) ~ IntVector { seen := IntMap->New(); max := 0; maxElems := IntVector->New(); each(i : coll) { value := coll[i]; featched := seen->Find(value)->As(IntHolder); if(featched <> Nil) { seen->Remove(value); seen->Insert(value, IntHolder->New(featched->Get() + 1)); } else { seen->Insert(value, IntHolder->New(1)); }; featched := seen->Find(value)->As(IntHolder); if(featched->Get() > max) { max := featched->Get(); maxElems->Empty(); maxElems->AddBack(value); } else if(featched->Get() = max) { maxElems->AddBack(value); }; }; return maxElems; } function : Print(out : IntVector) ~ Nil { '['->Print(); each(i : out) { out->Get(i)->Print(); if(i + 1 < out->Size()) { ", "->Print(); }; }; ']'->PrintLine(); } } ## Objective-C #import <Foundation/Foundation.h> @interface NSArray (Mode) - (NSArray *)mode; @end @implementation NSArray (Mode) - (NSArray *)mode { NSCountedSet *seen = [NSCountedSet setWithArray:self]; int max = 0; NSMutableArray *maxElems = [NSMutableArray array]; for ( obj in seen ) { int count = [seen countForObject:obj]; if (count > max) { max = count; [maxElems removeAllObjects]; [maxElems addObject:obj]; } else if (count == max) { [maxElems addObject:obj]; } } return maxElems; } @end  ## OCaml let mode lst = let seen = Hashtbl.create 42 in List.iter (fun x -> let old = if Hashtbl.mem seen x then Hashtbl.find seen x else 0 in Hashtbl.replace seen x (old + 1)) lst; let best = Hashtbl.fold (fun _ -> max) seen 0 in Hashtbl.fold (fun k v acc -> if v = best then k :: acc else acc) seen []  # mode [1;3;6;6;6;6;7;7;12;12;17];; - : int list = [6] # mode [1;1;2;4;4];; - : int list = [4; 1]  ## Octave Of course Octave has the mode function; but it returns only the "lowest" mode if multiple modes are available. function m = mode2(v) sv = sort(v); % build two vectors, vals and c, so that % c(i) holds how many times vals(i) appears i = 1; c = []; vals = []; while (i <= numel(v) ) tc = sum(sv==sv(i)); % it would be faster to count % them "by hand", since sv is sorted... c = [c, tc]; vals = [vals, sv(i)]; i += tc; endwhile % stack vals and c building a 2-rows matrix x x = cat(1,vals,c); % sort the second row (frequencies) into t (most frequent % first) and take the "original indices" i ... [t, i] = sort(x(2,:), "descend"); % ... so that we can use them to sort columns according % to frequencies nv = x(1,i); % at last, collect into m (the result) all the values % having the same bigger frequency r = t(1); i = 1; m = []; while ( t(i) == r ) m = [m, nv(i)]; i++; endwhile endfunction  a = [1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]; mode2(a) mode(a) a = [1, 1, 2, 4, 4]; mode2(a) % returns 1 and 4 mode(a) % returns 1 only  ## ooRexx See the example at REXX, Version 2 for a version that returns multiple mode values. -- will work with just about any collection... call testMode .array~of(10, 9, 8, 7, 6, 5, 4, 3, 2, 1) call testMode .list~of(10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0, .11) call testMode .queue~of(30, 10, 20, 30, 40, 50, -100, 4.7, -11e2) ::routine testMode use arg list say "list =" list~makearray~toString("l", ", ") say "mode =" mode(list) say ::routine mode use arg list -- this is a good application for a bag -- add all of the items to the bag collector = .bag~new collector~putAll(list) -- now get a list of unique items indexes = .set~new~~putall(collector) count = 0 -- this is used to keep track of the maximums -- now see how many of each element we ended up with loop index over indexes items = collector~allat(index) newCount = items~items if newCount > count then do mode = items[1] count = newCount end end return mode  ## Oz declare fun {Mode Xs} Freq = {Dictionary.new} for X in Xs do Freq.X := {CondSelect Freq X 0} + 1 end MaxCount = {FoldL {Dictionary.items Freq} Max 0} in for Value#Count in {Dictionary.entries Freq} collect:C do if Count == MaxCount then {C Value} end end end in {Show {Mode [1 2 3 3 2 1 1]}} {Show {Mode [1 2 3 3 2 1]}} ## PARI/GP mode(v)={ my(count=1,r=1,b=v[1]); v=vecsort(v); for(i=2,#v, if(v[i]==v[i-1], count++ , if(count>r, r=count; b=v[i-1] ); count=1 ) ); if(count>r,v[#v],b) }; ## Perl use strict; use List::Util qw(max); sub mode { my %c; foreach my$e ( @_ ) {
$c{$e}++;
}
my $best = max(values %c); return grep {$c{$_} ==$best } keys %c;
}

print "$_ " foreach mode(1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17); print "\n"; print "$_ " foreach mode(1, 1, 2, 4, 4);
print "\n";


## Phix

function mode(sequence s)
-- returns a list of the most common values, each of which occurs the same number of times
integer nxt = 1, count = 1, maxc = 1
sequence res = {}
if length(s)!=0 then
s = sort(s)
object prev = s[1]
for i=2 to length(s) do
if s[i]!=prev then
s[nxt] = {count,prev}
nxt += 1
prev = s[i]
count = 1
else
count += 1
if count>maxc then
maxc = count
end if
end if
end for
s[nxt] = {count,prev}
res = ""
for i=1 to nxt do
if s[i][1]=maxc then
res = append(res,s[i][2])
end if
end for
end if
return res
end function

?mode({1, 2, 5, -5, -9.5, 3.14159})
?mode({ 1, "blue", 2, 7.5, 5, "green", "red", 5, 2, "blue", "white" })
?mode({1, 2, 3, 1, 2, 4, 2, 5, 2, 3, 3, 1, 3, 6})
?mode({.2, .7, .1, .8, .2})
?mode({"two", 7, 1, 8, "two", 8})
?mode("Hello there world")
?mode({})
{} = wait_key()

Output:
{-9.5,-5,1,2,3.14159,5}
{2,5,"blue"}
{2,3}
{0.2}
{8,"two"}
"el"
{}


## PHP

Note: this function only works with strings and integers, as those are the only things that can be used as keys of an (associative) array in PHP.

<?php
function mode($arr) {$count = array_count_values($arr);$best = max($count); return array_keys($count, $best); } print_r(mode(array(1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17))); print_r(mode(array(1, 1, 2, 4, 4))); ?>  ## PicoLisp (de modes (Lst) (let A NIL (for X Lst (accu 'A X 1) ) (mapcar car (maxi cdar (by cdr group A) ) ) ) ) Output: : (modes (1 3 6 6 6 6 7 7 12 12 17)) -> (6) : (modes (1 1 2 4 4)) -> (4 1) : (modes (chop "ABRAHAMASANTACLARA")) -> ("A") : (modes (1 4 A 3 2 7 1 B B 3 6 2 4 C C 5 2 5 B A 3 2 C 3 5 5 4 C 7 7)) -> (5 C 2 3) ## PL/I av: procedure options (main); /* 28 October 2013 */ declare x(10) fixed binary static initial (1, 4, 2, 6, 2, 5, 6, 2, 4, 2); declare f(32767) fixed binary; declare (j, n, max, value) fixed binary; declare i fixed; n = hbound(x,1); do i = 1 to n; j = x(i); f(j) = f(j) + 1; end; max = 0; do i = 1 to hbound(f,1); if max < f(i) then do; max = f(i); value = i; end; end; put list ('The mode value is ' || value || ' occurred ' || max || ' times.'); end av; Results: The mode value is 2 occurred 4 times.  ## PowerShell $data = @(1,1,1,2,3,4,5,5,6,7,7,7)
$groups =$data | group-object | sort-object count -Descending
$groups | ? {$_.Count -eq $groups[0].Count}  Output: Count Name Group ----- ---- ----- 3 7 {7, 7, 7} 3 1 {1, 1, 1} ## PureBasic Procedure mean(Array InArray(1)) Structure MyMean Value.i Cnt.i EndStructure Protected i, max, found Protected NewList MyDatas.MyMean() Repeat found=#False ForEach MyDatas() If InArray(i)=MyDatas()\Value MyDatas()\Cnt+1 found=#True Break EndIf Next If Not found AddElement(MyDatas()) MyDatas()\Value=InArray(i) MyDatas()\cnt+1 EndIf If MyDatas()\Cnt>max max=MyDatas()\Cnt EndIf i+1 Until i>ArraySize(InArray()) ForEach MyDatas() If MyDatas()\Cnt=max For i=1 To max Print(Str(MyDatas()\Value)+" ") Next EndIf Next EndProcedure  ## Python The following solutions require that the elements be hashable. Works with: Python version 2.5+ and 3.x >>> from collections import defaultdict >>> def modes(values): count = defaultdict(int) for v in values: count[v] +=1 best = max(count.values()) return [k for k,v in count.items() if v == best] >>> modes([1,3,6,6,6,6,7,7,12,12,17]) [6] >>> modes((1,1,2,4,4)) [1, 4]  Works with: Python version 2.7+ and 3.1+ >>> from collections import Counter >>> def modes(values): count = Counter(values) best = max(count.values()) return [k for k,v in count.items() if v == best] >>> modes([1,3,6,6,6,6,7,7,12,12,17]) [6] >>> modes((1,1,2,4,4)) [1, 4]  If you just want one mode (instead of all of them), here's a one-liner for that: def onemode(values): return max(set(values), key=values.count)  ## Q mode:{(key x) where value x=max x} count each group @  ## Quackery  [ sort [] [] rot dup 0 peek temp put witheach [ dup temp share = iff join else [ dup temp replace dip [ nested join ] [] join ] ] nested join temp release ] is bunch ( [ --> [ ) [ sortwith [ size dip size < ] [] swap dup 0 peek size temp put witheach [ dup size temp share = iff [ nested join ] else [ drop conclude ] ] temp release [] swap witheach [ 0 peek join ] ] is largest ( [ --> [ ) [ bunch largest ] is mode ( [ --> [ ) ' [ 1 3 5 7 3 1 3 7 7 3 3 ] mode echo cr ' [ 7 13 5 13 7 2 7 10 13 ] mode echo cr ' [ 5 ] mode echo cr Output: [ 3 ] [ 7 13 ] [ 5 ]  ## R statmode <- function(v) { a <- sort(table(v), decreasing=TRUE) r <- c() for(i in 1:length(a)) { if ( a[[1]] == a[[i]] ) { r <- c(r, as.integer(names(a)[i])) } else break; # since it's sorted, once we find # a different value, we can stop } r } print(statmode(c(1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17))) print(statmode(c(1, 1, 2, 4, 4)))  ## Racket Returns values of list of modes and their frequencies of appearance. #lang racket (define (mode seq) (define frequencies (make-hash)) (for ([s seq]) (hash-update! frequencies s (lambda (freq) (add1 freq)) 0)) (for/fold ([ms null] [freq 0]) ([(k v) (in-hash frequencies)]) (cond [(> v freq) (values (list k) v)] [(= v freq) (values (cons k ms) freq)] [else (values ms freq)])))  ## Raku (formerly Perl 6) Works with: Rakudo version 2019.03.1 sub mode (*@a) { my %counts := @a.Bag; my$max = %counts.values.max;
%counts.grep(*.value == $max).map(*.key); } # Testing with arrays: say mode [1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]; say mode [1, 1, 2, 4, 4];  Output: 6 (4 1)  Alternatively, a version that uses a single method chain with no temporary variables: (Same output with same input) sub mode (*@a) { @a.Bag # count elements .classify(*.value) # group elements with the same count .max(*.key) # get group with the highest count .value.map(*.key); # get elements in the group } say mode [1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]; say mode [1, 1, 2, 4, 4];  ## REXX ### version 1 Returns one mode value. /*REXX program finds the mode (most occurring element) of a vector. */ /* ════════vector═══════════ ═══show vector═══ ═════show result═════ */ v= 1 8 6 0 1 9 4 6 1 9 9 9 ; say 'vector='v; say 'mode='mode(v); say v= 1 2 3 4 5 6 7 8 9 11 10 ; say 'vector='v; say 'mode='mode(v); say v= 8 8 8 2 2 2 ; say 'vector='v; say 'mode='mode(v); say v='cat kat Cat emu emu Kat' ; say 'vector='v; say 'mode='mode(v); say exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ sort: procedure expose @.; parse arg # 1 h /* [↓] this is an exchange sort. */ do while h>1; h=h%2 /*In REXX, % is an integer divide.*/ do i=1 for #-h; j=i; k=h+i /* [↓] perform exchange for elements. */ do while @.k<@.j & h<j; _=@.j; @.j=@.k; @.k=_; j=j-h; k=k-h; end end /*i*/ end /*while h>1*/; return /*──────────────────────────────────────────────────────────────────────────────────────*/ mode: procedure expose @.; parse arg x; freq=1 /*function finds the MODE of a vector*/ #=words(x) /*#: the number of elements in vector.*/ do k=1 for #; @.k=word(x,k); end /* ◄──── make an array from the vector.*/ call Sort # /*sort the elements in the array. */ ?=@.1 /*assume the first element is the mode.*/ do j=1 for #; _=j-freq /*traipse through the elements in array*/ if @.j==@._ then do; freq=freq+1 /*is this element the same as previous?*/ ?=@.j /*this element is the mode (···so far).*/ end end /*j*/ return ? /*return the mode of vector to invoker.*/  output vector=1 8 6 0 1 9 4 6 1 9 9 9 mode=9 vector=1 2 3 4 5 6 7 8 9 11 10 mode=1 vector=8 8 8 2 2 2 mode=2 vector=cat kat Cat emu emu Kat mode=emu  ### version 2 Translation of: NetRexx Works with: ooRexx Works with: Regina and should work for every REXX. /* Rexx */ /*-- ~~ main ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ call run_samples return exit /*-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ /*-- returns a comma separated string of mode values from a comma separated input vector string */ mode: procedure parse arg lvector drop vector. vector. = '' call makeStem lvector /*-- this call creates the "vector." stem from the input string */ seen. = 0 modes. = '' modeMax = 0 do v_ = 1 to vector.0 mv = vector.v_ seen.mv = seen.mv + 1 select when seen.mv > modeMax then do modeMax = seen.mv drop modes. modes. = '' nx = 1 modes.0 = nx modes.nx = mv end when seen.mv = modeMax then do nx = modes.0 + 1 modes.0 = nx modes.nx = mv end otherwise do nop end end end v_ lmodes = '' do e_ = 1 to modes.0 lmodes = lmodes modes.e_ end e_ lmodes = strip(space(lmodes, 1, ',')) return lmodes /*-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ /*-- pretty-print */ show_mode: procedure parse arg lvector lmodes = mode(lvector) say 'Vector: ['space(lvector, 0)'], Mode(s): ['space(lmodes, 0)']' return modes /*-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ /*-- load the "vector." stem from the comma separated input vector string */ makeStem: procedure expose vector. vector.0 = 0 parse arg lvector do v_ = 1 while lvector \= '' parse var lvector val ',' lvector vector.0 = v_ vector.v_ = strip(val) vector = strip(lvector) end v_ return vector.0 /*-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ run_samples: procedure call show_mode '10, 9, 8, 7, 6, 5, 4, 3, 2, 1' -- 10 9 8 7 6 5 4 3 2 1 call show_mode '10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0, 0.11' -- 0 call show_mode '30, 10, 20, 30, 40, 50, -100, 4.7, -11e+2' -- 30 call show_mode '30, 10, 20, 30, 40, 50, -100, 4.7, -11e+2, -11e+2' -- 30 -11e2 call show_mode '1, 8, 6, 0, 1, 9, 4, 6, 1, 9, 9, 9' -- 9 call show_mode '1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11' -- 1 2 3 4 5 6 7 8 9 10 11 call show_mode '8, 8, 8, 2, 2, 2' -- 8 2 call show_mode 'cat, kat, Cat, emu, emu, Kat' -- emu call show_mode '0, 1, 2, 3, 3, 3, 4, 4, 4, 4, 1, 0' -- 4 call show_mode '2, 7, 1, 8, 2' -- 2 call show_mode '2, 7, 1, 8, 2, 8' -- 8 2 call show_mode 'E, n, z, y, k, l, o, p, ä, d, i, e' -- E n z y k l o p ä d i e call show_mode 'E, n, z, y, k, l, o, p, ä, d, i, e, ä' -- ä call show_mode '3, 1, 4, 1, 5, 9, 7, 6' -- 1 call show_mode '3, 1, 4, 1, 5, 9, 7, 6, 3' -- 3, 1 call show_mode '1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17' -- 6 call show_mode '1, 1, 2, 4, 4' -- 4 1 return  Output: Vector: [10,9,8,7,6,5,4,3,2,1], Mode(s): [10,9,8,7,6,5,4,3,2,1] Vector: [10,9,8,7,6,5,4,3,2,1,0,0,0,0,0.11], Mode(s): [0] Vector: [30,10,20,30,40,50,-100,4.7,-11e+2], Mode(s): [30] Vector: [30,10,20,30,40,50,-100,4.7,-11e+2,-11e+2], Mode(s): [30,-11e+2] Vector: [1,8,6,0,1,9,4,6,1,9,9,9], Mode(s): [9] Vector: [1,2,3,4,5,6,7,8,9,10,11], Mode(s): [1,2,3,4,5,6,7,8,9,10,11] Vector: [8,8,8,2,2,2], Mode(s): [8,2] Vector: [cat,kat,Cat,emu,emu,Kat], Mode(s): [emu] Vector: [0,1,2,3,3,3,4,4,4,4,1,0], Mode(s): [4] Vector: [2,7,1,8,2], Mode(s): [2] Vector: [2,7,1,8,2,8], Mode(s): [2,8] Vector: [E,n,z,y,k,l,o,p,ä,d,i,e], Mode(s): [E,n,z,y,k,l,o,p,ä,d,i,e] Vector: [E,n,z,y,k,l,o,p,ä,d,i,e,ä], Mode(s): [ä] Vector: [3,1,4,1,5,9,7,6], Mode(s): [1] Vector: [3,1,4,1,5,9,7,6,3], Mode(s): [1,3] Vector: [1,3,6,6,6,6,7,7,12,12,17], Mode(s): [6] Vector: [1,1,2,4,4], Mode(s): [1,4] ## Ring # Project : Averages/Mode a = [1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17] b = [1, 2, 4, 4, 1] amodes = list(12) see "mode(s) of a() = " + nl for i1 = 1 to modes(a,amodes) see "" + amodes[i1] + " " next see nl see "mode(s) of b() = " + nl for i1 = 1 to modes(b,amodes) see "" + amodes [i1] + " " next see nl func modes(a,amodes) max = 0 n = len(a) if n = 0 amodes[1] = a[1] return 1 ok c = list(n) for i = 1 to n for j = i+1 to n if a[i] = a[j] c[i] = c[i] + 1 ok next if c[i] > max max = c[i] ok next j = 0 for i = 1 to n if c[i] = max j = j + 1 amodes[j] = a[i] ok next return j Output: mode(s) of a() = 6 mode(s) of b() = 1 4  ## RPL ∑VAL and ∑CNT are global lists used to store rep. values and counters. Using the stack to handle potentially big amounts of data would slow down execution. Works with: Halcyon Calc version 4.2.7 RPL code Comment  ≪ IF ∑VAL OVER POS THEN '∑CNT' LAST ∑CNT OVER GET 1 + PUT DROP ELSE ∑VAL SWAP + '∑VAL' STO ∑CNT 1 + '∑CNT' STO END ≫ '∑ADD' STO ≪ → data ≪ { } DUP '∑VAL' STO '∑CNT' STO 1 data SIZE FOR j data j GET ∑ADD NEXT ∑CNT LIST→ { } + →ARRY RNRM { } 1 ∑VAL SIZE FOR j IF OVER '∑CNT' j GET == THEN '∑VAL' j GET IF DUP2 POS NOT THEN + END END NEXT ≫ 'MODE' STO  ∑ADD ( n -- ) // update ∑VAL and ∑CNT if n already in ∑VAL then increment corresponding position in ∑CNT else create new in ∑VAL / ∑CNT entries MODE ( { data } -- { modal value(s) } ) initialize ∑VAL and ∑CNT for all input values count occurrences get max value in ∑CNT for all distinct values if count = max then get value and add it to output list if not already in  { 1 3 6 6 6 6 7 7 12 12 17 } MODE { 1 1 2 4 4 } MODE  Output: 2: { 6 } 1: { 1 4 }  ## Ruby Here's two methods, the first more Ruby-ish, the second perhaps a bit more efficient. def mode(ary) seen = Hash.new(0) ary.each {|value| seen[value] += 1} max = seen.values.max seen.find_all {|key,value| value == max}.map {|key,value| key} end def mode_one_pass(ary) seen = Hash.new(0) max = 0 max_elems = [] ary.each do |value| seen[value] += 1 if seen[value] > max max = seen[value] max_elems = [value] elsif seen[value] == max max_elems << value end end max_elems end p mode([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]) # => [6] p mode([1, 1, 2, 4, 4]) # => [1, 4] p mode_one_pass([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]) # => [6] p mode_one_pass([1, 1, 2, 4, 4]) # => [1, 4]  Works with: Ruby version 1.8.7 If you just want one mode (instead of all of them), here's a one-liner for that: def one_mode(ary) ary.max_by { |x| ary.count(x) } end  ## Rust use std::collections::HashMap; fn main() { let mode_vec1 = mode(vec![ 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]); let mode_vec2 = mode(vec![ 1, 1, 2, 4, 4]); println!("Mode of vec1 is: {:?}", mode_vec1); println!("Mode of vec2 is: {:?}", mode_vec2); assert!( mode_vec1 == [6], "Error in mode calculation"); assert!( (mode_vec2 == [1, 4]) || (mode_vec2 == [4,1]), "Error in mode calculation" ); } fn mode(vs: Vec<i32>) -> Vec<i32> { let mut vec_mode = Vec::new(); let mut seen_map = HashMap::new(); let mut max_val = 0; for i in vs{ let ctr = seen_map.entry(i).or_insert(0); *ctr += 1; if *ctr > max_val{ max_val = *ctr; } } for (key, val) in seen_map { if val == max_val{ vec_mode.push(key); } } vec_mode }  Output:  Mode of vec1 is: [6] Mode of vec2 is: [1,4] // may also print [4, 1], vector has no order guarantee  ## S-lang I'm accepting strings and numbers, although I'm converting numbers to strings, as S-Lang Assoc_Type only accepts strings as keys. private variable mx, mxkey, modedat; define find_max(key) { if (modedat[key] > mx) { mx = modedat[key]; mxkey = {key}; } else if (modedat[key] == mx) { list_append(mxkey, key); } } define find_mode(indat) { % reset [file/module-scope] globals: mx = 0, mxkey = {}, modedat = Assoc_Type[Int_Type, 0]; foreach$1 (indat)
modedat[string($1)]++; array_map(Void_Type, &find_max, assoc_get_keys(modedat)); if (length(mxkey) > 1) {$2 = 0;
() = printf("{");
foreach $1 (mxkey) { () = printf("%s%s",$2 ? ", " : "", $1);$2 = 1;
}
() = printf("} each have ");
}
else
() = printf("%s has ", mxkey[0], mx);
() = printf("the most entries (%d).\n", mx);
}

find_mode({"foo", "2.3", "bar", "foo", "foobar", "quality", 2.3, "strnen"});
Output:
Hungadunga has the most entries (4).
{foo, 2.3} each have the most entries (2).

## Scala

Works with: Scala version 2.8

Receiving any collection is easy. Returning the result in the same collection takes some doing.

import scala.collection.breakOut
import scala.collection.generic.CanBuildFrom
def mode
[T, CC[X] <: Seq[X]](coll: CC[T])
(implicit o: T => Ordered[T], cbf: CanBuildFrom[Nothing, T, CC[T]])
: CC[T] = {
val grouped = coll.groupBy(x => x).mapValues(_.size).toSeq
val max = grouped.map(_._2).max
grouped.filter(_._2 == max).map(_._1)(breakOut)
}


## Scheme

Works with: Berkeley Scheme
(define (mode collection)
(define (helper collection counts)
(if (null? collection)
counts
(helper (remove (car collection) collection)
(cons (cons (car collection)
(appearances (car collection) collection)) counts))))
(map car
(filter (lambda (x) (= (cdr x) (apply max (map cdr (helper collection '())))))
(helper collection '())))


## Seed7

The example below defines the template function createModeFunction, which defines the function mode. The template createModeFunction is instantiated explicit with createModeFunction(integer). Additionally to mode the function str is defined. The function str is used by the template function enable_output to allow writing arrays. This way the main function can just write the mode.

$include "seed7_05.s7i"; const proc: createModeFunction (in type: elemType) is func begin const func array elemType: mode (in array elemType: data) is func result var array elemType: maxElems is 0 times elemType.value; local var hash [elemType] integer: counts is (hash [elemType] integer).value; var elemType: aValue is elemType.value; var integer: maximum is 0; begin for aValue range data do if aValue in counts then incr(counts[aValue]); else counts @:= [aValue] 1; end if; if counts[aValue] > maximum then maximum := counts[aValue]; maxElems := [] (aValue); elsif counts[aValue] = maximum then maxElems &:= aValue; end if; end for; end func; const func string: str (in array elemType: data) is func result var string: stri is ""; local var elemType: anElement is elemType.value; begin for anElement range data do stri &:= " " & str(anElement); end for; stri := stri[2 ..]; end func; enable_output(array elemType); end func; createModeFunction(integer); const proc: main is func begin writeln(mode([] (1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17))); writeln(mode([] (1, 1, 2, 4, 4))); end func; Output: 6 1 4  ## Sidef func mode(array) { var c = Hash.new; array.each{|i| c{i} := 0 ++}; var max = c.values.max; c.keys.grep{|i| c{i} == max}; }  Calling the function say mode([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]).join(' '); say mode([1, 1, 2, 4, 4]).join(' ');  Output: 6 1 4  If you just want one mode (instead of all of them), here's a one-liner for that: func one_mode(arr) { arr.max_by{|i| arr.count(i)}; }  ## Slate s@(Sequence traits) mode [| sortedCounts | sortedCounts: (s as: Bag) sortedCounts. (sortedCounts mapSelect: [| :count :elem | sortedCounts last count = count]) valueSet ]. ## Smalltalk Works with: GNU Smalltalk This code is able to find the mode of any collection of any kind of object. OrderedCollection extend [ mode [ |s| s := self asBag sortedByCount. ^ (s select: [ :k | ((s at: 1) key) = (k key) ]) collect: [:k| k value] ] ]. #( 1 3 6 6 6 6 7 7 12 12 17 ) asOrderedCollection mode displayNl. #( 1 1 2 4 4) asOrderedCollection mode displayNl.  ## SQL Some databases have a built-in function. In Oracle you can say select stats_mode(val) from... but that returns one value, so doesn't handle non-unique modes. Other databases don't have a built-in. So here's a way to do this in a query. -- setup create table averages (val integer); insert into averages values (1); insert into averages values (2); insert into averages values (3); insert into averages values (1); insert into averages values (2); insert into averages values (4); insert into averages values (2); insert into averages values (5); insert into averages values (2); insert into averages values (3); insert into averages values (3); insert into averages values (1); insert into averages values (3); insert into averages values (6); -- find the mode with counts as ( select val, count(*) as num from averages group by val ) select val as mode_val from counts where num in (select max(num) from counts);  Output:  MODE_VAL ---------- 2 3 ## Swift Works with: Swift version 4 This solution uses an extension of the Collection type to add a mode method. The only additional requirement of the Collection is that its Element conforms to Hashable.  // Extend the Collection protocol. Any type that conforms to extension where its Element type conforms to Hashable will automatically gain this method. extension Collection where Element: Hashable { /// Return a Mode of the function, or nil if none exist. func mode() -> Element? { var frequencies = [Element: Int]() // Standard for loop. Can also use the forEach(_:) or reduce(into:) methods on self. for element in self { frequencies[element] = (frequencies[element] ?? 0) + 1 } // The max(by:) method used here to find one of the elements with the highest associated count. if let ( mode, _ ) = frequencies.max(by: {$0.value < $1.value }) { return mode } else { return nil } } } ["q", "a", "a", "a", "a", "b", "b", "z", "c", "c", "c"].mode() // returns "a" [1, 1, 2, 3, 3, 3, 3, 4, 4, 4].mode() // returns 3 let emptyArray: [Int] = [] emptyArray.mode() // returns nil  ## Tcl Works with: Tcl version 8.6 # Can find the modal value of any vector of values proc mode {n args} { foreach n [list$n {*}$args] { dict incr counter$n
}
set counts [lsort -stride 2 -index 1 -decreasing $counter] set best {} foreach {n count}$counts {
if {[lindex $counts 1] ==$count} {
lappend best $n } else break } return$best
}

# Testing
puts [mode 1 3 6 6 6 6 7 7 12 12 17];  # --> 6
puts [mode 1 1 2 4 4];  # --> 1 4


Note that this works for any kind of value.

## UNIX Shell

Works with: bash version 4.0
#!/bin/bash

function mode {
declare -A map
max=0
for x in "$@"; do tmp=$((${map[$x]} + 1))
map[$x]=$tmp
((tmp > max)) && max=$tmp done for x in "${!map[@]}"; do
[[ ${map[$x]} == $max ]] && echo -n "$x "
done
echo
}

mode 1 2 1 2 a b a b a 2
a 2


## Ursala

The mode function defined below works on lists of any type and returns a list of the modes. There is no concept of a general collection in Ursala. The algorithm is to partition the list by equality, then partition the classes by their lengths, and then select a representative from each member of the set of classes with the maximum length.

#import std

mode = ~&hS+ leql$^&h+ eql|=@K2 #cast %nLW examples = mode~~ (<1,3,6,6,6,7,7,12,12,17>,<1,1,2,4,4>) The function is tested on a pair of lists, one with a unique mode and one with multiple modes. Output: (<6>,<4,1>) ## VBA Using an array of integers to show the built-in Mode_Mult function, which find and displays the modes in an array. The function ignores text and only works for numbers. Public Sub main() s = [{1,2,3,3,3,4,4,4,5,5,6}] t = WorksheetFunction.Mode_Mult(s) For Each x In t Debug.Print x; Next x End Sub  Output:  3 4 ## Vedit macro language Current edit buffer stores the collection. Each line is an item in the collection. The items can be any type (ascii text, numeric values in ascii, binary values). However, binary file with fixed record length would require some modifications to the code. The "mode" item and it's count are displayed on status line. If there are multiple items with the same count, the smallest one is displayed. BOF // Copy all data to a new buffer Reg_Copy(10, ALL) Buf_Switch(Buf_Free) Reg_Ins(10) Sort(0, File_Size) // Sort the data BOF repeat(ALL) { // Count & delete duplicate lines #1 = 1 while(Match("^{.*}\N\1$", REGEXP)==0) {
Del_Line(1)
#1++
}
Num_Ins(#1, NOCR)             // Insert item count at the beginning of line
Ins_Char(9)                   // TAB
Line(1, ERRBREAK)             // Next (different) line
}

Sort(0, File_Size, REVERSE)       // Sort according to the count

BOF                               // Display the results
Reg_Copy_Block(10, CP, EOL_pos)
Buf_Quit(OK)
Statline_Message(@10)

## V (Vlang)

fn main() {
println(mode([2, 7, 1, 8, 2]))
println(mode([2, 7, 1, 8, 2, 8]))
}

fn mode(a []int) []int {
mut m := map[int]int{}
for v in a {
m[v]++
}
mut mode := []int{}
mut n := 0
for k, v in m {
match true {
v > n {
n = v
mode = [k]
}
v<n{}
else {
mode << k
}
}
}
return mode
}
Output:
[2]
[2, 8]


Or using math.stats module

import math.stats
fn main() {
println(stats.mode<int>([2, 7, 1, 8, 2]))
println(stats.mode<int>([2, 7, 1, 8, 2, 8]))
}
Output:
2
2


## Wren

class Arithmetic {
static mode(arr) {
var map = {}
for (e in arr) {
if (map[e] == null) map[e] = 0
map[e] = map[e] + 1
}
var max = map.values.reduce {|x, y| x > y ? x : y}
return map.keys.where {|x| map[x] == max}.toList
}
}

System.print(Arithmetic.mode([1,2,3,4,5,5,51,2,3]))

Output:

[2, 3, 5]

Order may differ

## XEmacs Lisp

This returns a list of the modes. Any type(s) of data can be passed in, and any "equal" predicate function can be specified.

(defun mode ( predicate &rest values)
"Finds the mode of all values passed in.
Uses predicate' to compare items."
(let ((modes nil)                                      ; Declare local variables
(mode-count 0)
(value-list nil)
current-value)
(loop for value in values do
(if (setq current-value (assoc* value value-list :test predicate)) ; Construct a linked list of cons cells, (value . count)
(incf (cdr current-value))
(push (cons value 1) value-list)))
(loop for (value . count) in value-list do           ; Find modes in linked list
(if (> count mode-count)
(setq modes (list value)
mode-count count)
(when (eq count mode-count)
(push value modes))))
modes))

## XPL0

proc Mode(Size, Array);         \Show the mode(s) of Array
int  Size, Array;
int  List, Count I, J, K, Max;
[List:= Reserve(Size*4);        \4 bytes per integer
Count:= Reserve(Size*4);
K:= 0;
for I:= 0 to Size-1 do
[for J:= 0 to K-1 do
if List(J) = Array(I) then  \item is in List
[Count(J):= Count(J)+1; \ so increment its count
J:= Size;
];
if J = K then               \not already in List
[List(K):= Array(I);
Count(K):= 1;
K:= K+1;
];
];
Max:= 0;                        \find maximum count
for J:= 0 to K-1 do
if Count(J) > Max then
Max:= Count(J);
for J:= 0 to K-1 do             \show Array item(s) with Max Count
if Count(J) = Max then
[IntOut(0, List(J));  ChOut(0, ^ )];
];

Mode(9, [1,2,3,4,5,5,5123,2,3])
Output:
2 3 5 

## Yabasic

sub floor(x)
return int(x + .05)
end sub

SUB ASort$(matriz$())
local last, gap, first, tempi$, tempj$, i, j

last = arraysize(matriz$(), 1) gap = floor(last / 10) + 1 while(TRUE) first = gap + 1 for i = first to last tempi$ = matriz$(i) j = i - gap while(TRUE) tempj$ = matriz$(j) if (tempi$ >= tempj$) then j = j + gap break end if matriz$(j+gap) = tempj$if j <= gap then break end if j = j - gap wend matriz$(j) = tempi$next i if gap = 1 then return else gap = floor(gap / 3.5) + 1 end if wend END SUB sub getMode$(list$) // returns mode and count local m$(1), n, i, mode$, count, maxM$, maxC

n = token(list$, m$(), ", ")
ASort$(m$())

for i = 1 to n
if m$(i) <> mode$ then
if count > maxC then
maxM$= mode$
maxC = count
end if
count = 1
mode$= m$(i)
else
count = count + 1
end if
next i

return maxM$+ "," + str$(maxC)
end sub

result$= getMode$("1,3,6,6,6,6,7,7,12,12,17")
n = instr(result$, ",") print "mode ", left$(result$, n - 1), " occur(s) ", right$(result$, len(result$) - n), " times."

result$= getMode$("a, a, b, d, d")
print "mode ", left$(result$, n - 1), " occur(s) ", right$(result$, len(result\$) - n), " times."
Output:
mode 6 occur(s) 4 times.
mode a occur(s) 2 times.

## zkl

This is a bit funky in that modes are returned as strings.

Translation of: D
fcn mode(items){
d:=Dictionary(); foreach i in (items){ d.incV(i) }
m:=d.reduce(fcn(m,[(_,v)]){ v.max(m) },0);
d.filter('wrap([(_,v)]){ v==m }).apply("get",0);
}
data:=T(1, 2, 3, 1, 2, 4, 2, 5, 3, 3, 1, 3, 6);
println("Mode: ", mode(data));
println("Mode: ", mode(data.append(2)));
println("Mode: ", mode("this is a test".split("")));
Output:
Mode: L("3")
Mode: L("2","3")
Mode: L("s","t"," ")
`