Sorting algorithms/Selection sort: Difference between revisions

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Replaced content with "-module(solution). -import(lists,[delete/2,max/1]). -compile(export_all). selection_sort([],Sort)-> Sort; selection_sort(Ar,Sort)-> M=max(Ar), Ad=delete(M,Ar), selectio..."
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-module(solution).
{{task|Sorting Algorithms}}{{Sorting Algorithm}}
-import(lists,[delete/2,max/1]).
-compile(export_all).
selection_sort([],Sort)-> Sort;
selection_sort(Ar,Sort)->
M=max(Ar),
Ad=delete(M,Ar),
selection_sort(Ad,[M|Sort]).
print_array([])->ok;
print_array([H|T])->
io:format("~p~n",[H]),
print_array(T).


main()->
;Task:
Ans=selection_sort([1,5,7,8,4,10],[]),
Sort an [[array]] (or list) of elements using the Selection sort algorithm.
print_array(Ans).


It works as follows:

First find the smallest element in the array and exchange it with the element in the first position, then find the second smallest element and exchange it with the element in the second position, and continue in this way until the entire array is sorted.


Its asymptotic complexity is &nbsp; <big> [[O]](n<sup>2</sup>) </big> &nbsp; making it inefficient on large arrays.

Its primary purpose is for when writing data is very expensive (slow) when compared to reading, eg. writing to flash memory or EEPROM.

No other sorting algorithm has less data movement.


;Reference:
* Wikipedia: &nbsp; [[wp:Selection_sort|Selection sort]]
<br><br>

=={{header|360 Assembly}}==
{{trans|PL/I}}
The program uses ASM structured macros and two ASSIST macros to keep the code as short as possible.
<lang 360asm>* Selection sort 26/06/2016
SELECSRT CSECT
USING SELECSRT,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
STM R14,R12,12(R13) prolog
ST R13,4(R15) "
ST R15,8(R13) "
LR R13,R15 "
LA RJ,1 j=1
DO WHILE=(C,RJ,LE,N) do j=1 to n
LR RK,RJ k=j
LR R1,RJ j
SLA R1,2 .
LA R3,A-4(R1) @a(j)
L RT,0(R3) temp=a(j)
LA RI,1(RJ) i=j+1
DO WHILE=(C,RI,LE,N) do i=j+1 to n
LR R1,RI i
SLA R1,2 .
L R2,A-4(R1) a(i)
IF CR,RT,GT,R2 THEN if temp>a(i) then
LR RT,R2 temp=a(i)
LR RK,RI k=i
ENDIF , end if
LA RI,1(RI) i=i+1
ENDDO , end do
L R0,0(R3) a(j)
LR R1,RK k
SLA R1,2 .
ST R0,A-4(R1) a(k)=a(j)
ST RT,0(R3) a(j)=temp;
LA RJ,1(RJ) j=j+1
ENDDO , end do
LA R3,PG pgi=0
LA RI,1 i=1
DO WHILE=(C,RI,LE,N) do i=1 to n
LR R1,RI i
SLA R1,2 .
L R2,A-4(R1) a(i)
XDECO R2,XDEC edit a(i)
MVC 0(4,R3),XDEC+8 output a(i)
LA R3,4(R3) pgi=pgi+4
LA RI,1(RI) i=i+1
ENDDO , end do
XPRNT PG,L'PG print buffer
L R13,4(0,R13) epilog
LM R14,R12,12(R13) "
XR R15,R15 "
BR R14 exit
A DC F'4',F'65',F'2',F'-31',F'0',F'99',F'2',F'83',F'782',F'1'
DC F'45',F'82',F'69',F'82',F'104',F'58',F'88',F'112',F'89',F'74'
N DC A((N-A)/L'A) number of items of a
PG DC CL80' ' buffer
XDEC DS CL12 temp for xdeco
YREGS
RI EQU 6 i
RJ EQU 7 j
RK EQU 8 k
RT EQU 9 temp
END SELECSRT</lang>
{{out}}
<pre>
-31 0 1 2 2 4 45 58 65 69 74 82 82 83 88 89 99 104 112 782
</pre>

=={{header|ActionScript}}==
<lang ActionScript>function selectionSort(input: Array):Array {
//find the i'th element
for (var i:uint = 0; i < input.length; i++) {
//set minIndex to an arbitrary value
var minIndex:uint=i;
//find the smallest number
for (var j:uint = i; j < input.length; j++) {
if (input[j]<input[minIndex]) {
minIndex=j;
}
}
//swap the smallest number into place
var tmp:Number=input[i];
input[i]=input[minIndex];
input[minIndex]=tmp;
}
return input;
}</lang>

=={{header|Ada}}==
<lang ada>with Ada.Text_IO; use Ada.Text_IO;

procedure Test_Selection_Sort is

type Integer_Array is array (Positive range <>) of Integer;
procedure Sort (A : in out Integer_Array) is
Min : Positive;
Temp : Integer;
begin
for I in A'First..A'Last - 1 loop
Min := I;
for J in I + 1..A'Last loop
if A (Min) > A (J) then
Min := J;
end if;
end loop;
if Min /= I then
Temp := A (I);
A (I) := A (Min);
A (Min) := Temp;
end if;
end loop;
end Sort;

A : Integer_Array := (4, 9, 3, -2, 0, 7, -5, 1, 6, 8);
begin
Sort (A);
for I in A'Range loop
Put (Integer'Image (A (I)) & " ");
end loop;
end Test_Selection_Sort;</lang>
{{out}}
<pre>
-5 -2 0 1 3 4 6 7 8 9
</pre>

=={{header|ALGOL 68}}==
{{trans|Ada}}

{{works with|ALGOL 68|Standard - no extensions to language used}}
{{works with|ALGOL 68G|Any - tested with release mk15-0.8b.fc9.i386}}
{{works with|ELLA ALGOL 68|Any (with appropriate job cards) - tested with release 1.8.8d.fc9.i386}}
<lang algol68>MODE DATA = REF CHAR;

PROC in place selection sort = (REF[]DATA a)VOID:
BEGIN
INT min;
DATA temp;
FOR i FROM LWB a TO UPB a DO
min := i;
FOR j FROM i + 1 TO UPB a DO
IF a [min] > a [j] THEN
min := j
FI
OD;
IF min /= i THEN
temp := a [i];
a [i] := a [min];
a [min] := temp
FI
OD
END # in place selection sort #;
[32]CHAR data := "big fjords vex quick waltz nymph";
[UPB data]DATA ref data; FOR i TO UPB data DO ref data[i] := data[i] OD;
in place selection sort(ref data);
FOR i TO UPB ref data DO print(ref data[i]) OD; print(new line);
print((data))</lang>
{{out}}
<pre>
abcdefghiijklmnopqrstuvwxyz
big fjords vex quick waltz nymph
</pre>

=={{header|AutoHotkey}}==
ahk forum: [http://www.autohotkey.com/forum/topic44657-105.html discussion]
<lang AutoHotkey>MsgBox % SelecSort("")
MsgBox % SelecSort("xxx")
MsgBox % SelecSort("3,2,1")
MsgBox % SelecSort("dog,000000,xx,cat,pile,abcde,1,cat,zz,xx,z")

SelecSort(var) { ; SORT COMMA SEPARATED LIST
StringSplit a, var, `, ; make array, size = a0

Loop % a0-1 {
i := A_Index, mn := a%i%, j := m := i
Loop % a0-i { ; find minimum
j++
If (a%j% < mn)
mn := a%j%, m := j
}
t := a%i%, a%i% := a%m%, a%m% := t ; swap first with minimum
}
Loop % a0 ; construct string from sorted array
sorted .= "," . a%A_Index%
Return SubStr(sorted,2) ; drop leading comma
}</lang>

=={{header|AWK}}==
<lang awk>function getminindex(gl, gi, gs)
{
min = gl[gi]
gm = gi
for(gj=gi; gj <= gs; gj++) {
if ( gl[gj] < min ) {
min = gl[gj]
gm = gj
}
}
return gm
}

{
line[NR] = $0
}
END { # sort it with selection sort
for(i=1; i <= NR; i++) {
mi = getminindex(line, i, NR)
t = line[i]
line[i] = line[mi];
line[mi] = t
}
#print it
for(i=1; i <= NR; i++) {
print line[i]
}
}</lang>

=={{header|BBC BASIC}}==
<lang BBCBASIC>DEF PROC_SelectionSort(Size%)
FOR I% = 1 TO Size%-1
lowest% = I%
FOR J% = (I% + 1) TO Size%
IF data%(J%) < data%(lowest%) lowest% = J%
NEXT J%
IF I%<>lowest% SWAP data%(I%),data%(lowest%)
NEXT I%
ENDPROC</lang>

=={{header|C}}==

<lang c>#include <stdio.h>

void selection_sort (int *a, int n) {
int i, j, m, t;
for (i = 0; i < n; i++) {
for (j = i, m = i; j < n; j++) {
if (a[j] < a[m]) {
m = j;
}
}
t = a[i];
a[i] = a[m];
a[m] = t;
}
}

int main () {
int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1};
int n = sizeof a / sizeof a[0];
int i;
for (i = 0; i < n; i++)
printf("%d%s", a[i], i == n - 1 ? "\n" : " ");
selection_sort(a, n);
for (i = 0; i < n; i++)
printf("%d%s", a[i], i == n - 1 ? "\n" : " ");
return 0;
}
</lang>
{{out}}
<pre>
4 65 2 -31 0 99 2 83 782 1
-31 0 1 2 2 4 65 83 99 782
</pre>

=={{header|C++}}==
Uses C++11. Compile with
g++ -std=c++11 selection.cpp
<lang cpp>#include <algorithm>
#include <iterator>
#include <iostream>

template<typename ForwardIterator> void selection_sort(ForwardIterator begin,
ForwardIterator end) {
for(auto i = begin; i != end; ++i) {
std::iter_swap(i, std::min_element(i, end));
}
}

int main() {
int a[] = {100, 2, 56, 200, -52, 3, 99, 33, 177, -199};
selection_sort(std::begin(a), std::end(a));
copy(std::begin(a), std::end(a), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
}</lang>
{{out}}
<pre>
-199 -52 2 3 33 56 99 100 177 200
</pre>

=={{header|C sharp|C#}}==
This is a generic implementation that works with any type that implements the IComparable interface

<lang csharp>class SelectionSort<T> where T : IComparable {
public T[] Sort(T[] list) {
int k;
T temp;

for (int i = 0; i < list.Length; i++) {
k = i;
for (int j=i + 1; j < list.Length; j++) {
if (list[j].CompareTo(list[k]) < 0) {
k = j;
}
}
temp = list[i];
list[i] = list[k];
list[k] = temp;
}

return list;
}
}</lang>

Example of usage:
<lang csharp>String[] str = { "this", "is", "a", "test", "of", "generic", "selection", "sort" };

SelectionSort<String> mySort = new SelectionSort<string>();

String[] result = mySort.Sort(str);

for (int i = 0; i < result.Length; i++) {
Console.WriteLine(result[i]);
}</lang>

{{out}}
<pre>a
generic
is
of
selection
sort
test
this</pre>

=={{header|Clojure}}==
This is an implementation that mutates a Java arraylist in place.
<lang lisp>(import 'java.util.ArrayList)

(defn arr-swap! [#^ArrayList arr i j]
(let [t (.get arr i)]
(doto arr
(.set i (.get arr j))
(.set j t))))

(defn sel-sort!
([arr] (sel-sort! compare arr))
([cmp #^ArrayList arr]
(let [n (.size arr)]
(letfn [(move-min!
[start-i]
(loop [i start-i]
(when (< i n)
(when (< (cmp (.get arr i) (.get arr start-i)) 0)
(arr-swap! arr start-i i))
(recur (inc i)))))]
(doseq [start-i (range (dec n))]
(move-min! start-i))
arr))))</lang>

=={{header|COBOL}}==
<lang COBOL> PERFORM E-SELECTION VARYING WB-IX-1 FROM 1 BY 1
UNTIL WB-IX-1 = WC-SIZE.

...

E-SELECTION SECTION.
E-000.
SET WC-LOWEST TO WB-IX-1.
ADD 1 WC-LOWEST GIVING WC-START

PERFORM F-PASS VARYING WB-IX-2 FROM WC-START BY 1
UNTIL WB-IX-2 > WC-SIZE.

IF WB-IX-1 NOT = WC-LOWEST
MOVE WB-ENTRY(WC-LOWEST) TO WC-TEMP
MOVE WB-ENTRY(WB-IX-1) TO WB-ENTRY(WC-LOWEST)
MOVE WC-TEMP TO WB-ENTRY(WB-IX-1).

E-999.
EXIT.

F-PASS SECTION.
F-000.
IF WB-ENTRY(WB-IX-2) < WB-ENTRY(WC-LOWEST)
SET WC-LOWEST TO WB-IX-2.

F-999.
EXIT.</lang>

=={{header|Common Lisp}}==

<lang lisp>(defun selection-sort-vector (array predicate)
(do ((length (length array))
(i 0 (1+ i)))
((eql i length) array)
(do ((mindex i)
(min (aref array i))
(j i (1+ j)))
((eql j length)
(rotatef (aref array i) (aref array mindex)))
(when (funcall predicate (aref array j) min)
(setf min (aref array j)
mindex j)))))

(defun selection-sort-list (list predicate)
(flet ((min-first (list)
(do ((before-min nil)
(min (first list))
(prev list (rest prev))
(curr (rest list) (rest curr)))
((endp curr)
(if (null before-min) list
(let ((min (cdr before-min)))
(rplacd before-min (cdr min))
(rplacd min list)
min)))
(when (funcall predicate (first curr) min)
(setf before-min prev
min (first curr))))))
(let ((result (min-first list)))
(do ((head result (rest head)))
((endp (rest head)) result)
(rplacd head (min-first (rest head)))))))

(defun selection-sort (sequence predicate)
(etypecase sequence
(list (selection-sort-list sequence predicate))
(vector (selection-sort-vector sequence predicate))))</lang>

Example use:

<pre>> (selection-sort (list 8 7 4 3 2 0 9 1 5 6) '<)
(0 1 2 3 4 5 6 7 8 9)

> (selection-sort (vector 8 7 4 3 2 0 9 1 5 6) '>)
#(9 8 7 6 5 4 3 2 1 0)</pre>

=={{header|D}}==
The actual function is very short.
<lang d>import std.stdio, std.algorithm, std.array, std.traits;

enum AreSortableArrayItems(T) = isMutable!T &&
__traits(compiles, T.init < T.init) &&
!isNarrowString!(T[]);

void selectionSort(T)(T[] data) if (AreSortableArrayItems!T) {
foreach (immutable i, ref d; data)
data.drop(i).minPos[0].swap(d);
} unittest {
int[] a0;
a0.selectionSort;

auto a1 = [1];
a1.selectionSort;
assert(a1 == [1]);

auto a2 = ["a", "b"];
a2.selectionSort;
assert(a2 == ["a", "b"]);

auto a3 = ["b", "a"];
a3.selectionSort;
assert(a3 == ["a", "b"]);

auto a4 = ['a', 'b'];
static assert(!__traits(compiles, a4.selectionSort));

dchar[] a5 = ['b', 'a'];
a5.selectionSort;
assert(a5 == "ab"d);

import std.typecons;
alias Nullable!int N;
auto a6 = [N(2), N(1)];
a6.selectionSort; // Not nothrow.
assert(a6 == [N(1), N(2)]);

auto a7 = [1.0+0i, 2.0+0i]; // To be deprecated.
static assert(!__traits(compiles, a7.selectionSort));

import std.complex;
auto a8 = [complex(1), complex(2)];
static assert(!__traits(compiles, a8.selectionSort));

static struct F {
int x;
int opCmp(F f) { // Not pure.
return x < f.x ? -1 : (x > f.x ? 1 : 0);
}
}
auto a9 = [F(2), F(1)];
a9.selectionSort;
assert(a9 == [F(1), F(2)]);
}

void main() {
auto a = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3, 2];
a.selectionSort;
a.writeln;
}</lang>
{{out}}
<pre>[1, 1, 2, 2, 3, 3, 3, 4, 5, 5, 5, 6, 7, 8, 9, 9, 9]</pre>

=={{header|Delphi}}==

===Array sort===
Dynamic array is a 0-based array of variable length

Static array is an arbitrary-based array of fixed length
<lang Delphi>program TestSelectionSort;

{$APPTYPE CONSOLE}

{.$DEFINE DYNARRAY} // remove '.' to compile with dynamic array

type
TItem = Integer; // declare ordinal type for array item
{$IFDEF DYNARRAY}
TArray = array of TItem; // dynamic array
{$ELSE}
TArray = array[0..15] of TItem; // static array
{$ENDIF}

procedure SelectionSort(var A: TArray);
var
Item: TItem;
I, J, M: Integer;

begin
for I:= Low(A) to High(A) - 1 do begin
M:= I;
for J:= I + 1 to High(A) do
if A[J] < A[M] then M:= J;
Item:= A[M];
A[M]:= A[I];
A[I]:= Item;
end;
end;

var
A: TArray;
I: Integer;

begin
{$IFDEF DYNARRAY}
SetLength(A, 16);
{$ENDIF}
for I:= Low(A) to High(A) do
A[I]:= Random(100);
for I:= Low(A) to High(A) do
Write(A[I]:3);
Writeln;
SelectionSort(A);
for I:= Low(A) to High(A) do
Write(A[I]:3);
Writeln;
Readln;
end.</lang>
{{out}}
<pre>
0 3 86 20 27 67 31 16 37 42 8 47 7 84 5 29
0 3 5 7 8 16 20 27 29 31 37 42 47 67 84 86
</pre>

===String sort===
// string is 1-based variable-length array of Char
<lang Delphi>procedure SelectionSort(var S: string);
var
Lowest: Char;
I, J, M, L: Integer;

begin
L:= Length(S);
for I:= 1 to L - 1 do begin
M:= I;
for J:= I + 1 to L do
if S[J] < S[M] then M:= J;
Lowest:= S[M];
S[M]:= S[I];
S[I]:= Lowest;
end;
end;</lang>
<pre>
// in : S = 'the quick brown fox jumps over the lazy dog'
// out: S = ' abcdeeefghhijklmnoooopqrrsttuuvwxyz'
</pre>

=={{header|E}}==

<lang e>def selectionSort := {
def cswap(c, a, b) {
def t := c[a]
c[a] := c[b]
c[b] := t
println(c)
}
def indexOfMin(array, first, last) {
var min := array[first]
var mini := first
for i in (first+1)..last {
if (array[i] < min) {
min := array[i]
mini := i
}
}
return mini
}

/** Selection sort (in-place). */
def selectionSort(array) {
def last := (array.size()-1)
for i in 0..(last - 1) {
cswap(array, i, indexOfMin(array, i + 1, last))
}
}
}</lang>

=={{header|EchoLisp}}==
===List sort===
<lang scheme>
;; recursive version (adapted from Racket)
(lib 'list) ;; list-delete
(define (sel-sort xs (x0))
(cond
[(null? xs) null]
[else (set! x0 (apply min xs))
(cons x0 (sel-sort (list-delete xs x0)))]))

(sel-sort (shuffle (iota 13)))
→ (0 1 2 3 4 5 6 7 8 9 10 11 12)
;; straightforward and more efficient implementation using list-swap!
(define (sel-sort list)
(maplist (lambda( L)
(first (list-swap! L (first L) (apply min L )))) list))
(sel-sort (shuffle (iota 13)))
→ (0 1 2 3 4 5 6 7 8 9 10 11 12)
</lang>
===Array sort===
<lang scheme>
;; sort an array in place
(define (sel-sort a (amin) (imin))
(define ilast (1- (vector-length a)))
(for [(i ilast)]
(set! amin [a (setv! imin i)]) ;; imin := i , amin := a[imin]
(for [(j (in-range (1+ i) (1+ ilast)))]
(when (< [a j] amin) (set! amin [a (setv! imin j)])))
(vector-swap! a i imin))
a )
(define a #(9 8 2 6 3 5 4))
(sel-sort a)
→ #( 2 3 4 5 6 8 9)
</lang>


=={{header|Eiffel}}==

<lang Eiffel>
class
SELECTION_SORT [G -> COMPARABLE]

feature {NONE}

index_of_min (ar: ARRAY [G]; lower: INTEGER): INTEGER
--Index of smallest element in 'ar' in the range of lower and the max index.
require
lower_positiv: lower >= 1
lower_in_range: lower <= ar.count
ar_not_void: ar /= Void
local
i: INTEGER
min: G
do
from
i := lower
min := ar.item (i)
Result := i
until
i + 1 > ar.count
loop
if ar.item (i + 1) < min then
min := ar.item (i + 1)
Result := i + 1
end
i := i + 1
end
ensure
result_is_set: Result /= Void
end

sort (ar: ARRAY [G]): ARRAY [G]
-- sort array ar with selectionsort
require
ar_not_void: ar /= Void
local
min_index: INTEGER
ith: G
do
create Result.make_empty
Result.deep_copy (ar)
across
Result as ic
loop
min_index := index_of_min (Result, ic.cursor_index)
ith := Result [ic.cursor_index]
Result [ic.cursor_index] := Result [min_index]
Result [min_index] := ith
end
ensure
Result_is_set: Result /= Void
Result_sorted: is_sorted (Result) = True
end

is_sorted (ar: ARRAY [G]): BOOLEAN
--- Is 'ar' sorted in ascending order?
require
ar_not_empty: ar.is_empty = False
local
i: INTEGER
do
Result := True
from
i := ar.lower
until
i = ar.upper
loop
if ar [i] > ar [i + 1] then
Result := False
end
i := i + 1
end
end

feature

selectionsort (ar: ARRAY [G]): ARRAY [G]
do
Result := sort (ar)
end

end
</lang>
Test:
<lang eiffel>
class
APPLICATION

create
make

feature

make
do
test := <<1, 27, 32, 99, 1, -7, 3, 5, 7>>
io.put_string ("Unsorted: ")
across
test as ic
loop
io.put_string (ic.item.out + " ")
end
create selectionsort
io.put_string ("%NSorted: ")
test := selectionsort.selectionsort (test)
across
test as ar
loop
io.put_string (ar.item.out + " ")
end
end

test: ARRAY [INTEGER]

selectionsort: SELECTION_SORT [INTEGER]

end
</lang>
{{out}}
<pre>
Unsorted: 1 27 32 99 1 -7 3 5 7
Sorted: -7 1 1 3 5 7 27 32 99
</pre>

=={{header|Elixir}}==
<lang elixir>defmodule Sort do
def selection_sort(list) when is_list(list), do: selection_sort(list, [])
defp selection_sort([], sorted), do: sorted
defp selection_sort(list, sorted) do
max = Enum.max(list)
selection_sort(List.delete(list, max), [max | sorted])
end
end</lang>

Example:
<pre>
iex(10)> Sort.selection_sort([5,3,9,4,1,6,8,2,7])
[1, 2, 3, 4, 5, 6, 7, 8, 9]
</pre>

=={{header|Euphoria}}==
<lang euphoria>function selection_sort(sequence s)
object tmp
integer m
for i = 1 to length(s) do
m = i
for j = i+1 to length(s) do
if compare(s[j],s[m]) < 0 then
m = j
end if
end for
tmp = s[i]
s[i] = s[m]
s[m] = tmp
end for
return s
end function

include misc.e
constant s = {4, 15, "delta", 2, -31, 0, "alfa", 19, "gamma", 2, 13, "beta", 782, 1}

puts(1,"Before: ")
pretty_print(1,s,{2})
puts(1,"\nAfter: ")
pretty_print(1,selection_sort(s),{2})</lang>

{{out}}
<pre>Before: {
4,
15,
"delta",
2,
-31,
0,
"alfa",
19,
"gamma",
2,
13,
"beta",
782,
1
}
After: {
-31,
0,
1,
2,
2,
4,
13,
15,
19,
782,
"alfa",
"beta",
"delta",
"gamma"
}</pre>

=={{header|F Sharp|F#}}==
<lang fsharp>
let rec ssort = function
[] -> []
| x::xs ->
let min, rest =
List.fold_left (fun (min,acc) x ->
if h<min then (h, min::acc)
else (min, h::acc))
(x, []) xs
in min::ssort rest
</lang>

=={{header|Forth}}==
<lang forth>defer less? ' < is less?

: least ( start end -- least )
over cell+ do
i @ over @ less? if drop i then
cell +loop ;
: selection ( array len -- )
cells over + tuck ( end start end )
cell- swap do ( end )
i over least ( end least )
i @ over @ i ! swap !
cell +loop drop ;

create array 8 , 1 , 4 , 2 , 10 , 3 , 7 , 9 , 6 , 5 ,
array 10 selection
array 10 cells dump</lang>

=={{header|Fortran}}==
{{works with|Fortran|95 and later}}
<lang fortran>PROGRAM SELECTION

IMPLICIT NONE

INTEGER :: intArray(10) = (/ 4, 9, 3, -2, 0, 7, -5, 1, 6, 8 /)
WRITE(*,"(A,10I5)") "Unsorted array:", intArray
CALL Selection_sort(intArray)
WRITE(*,"(A,10I5)") "Sorted array :", intArray
CONTAINS
SUBROUTINE Selection_sort(a)
INTEGER, INTENT(IN OUT) :: a(:)
INTEGER :: i, minIndex, temp

DO i = 1, SIZE(a)-1
minIndex = MINLOC(a(i:), 1) + i - 1
IF (a(i) > a(minIndex)) THEN
temp = a(i)
a(i) = a(minIndex)
a(minIndex) = temp
END IF
END DO
END SUBROUTINE Selection_sort

END PROGRAM SELECTION</lang>
{{out}}
<pre>
Unsorted array: 4 9 3 -2 0 7 -5 1 6 8
Sorted array : -5 -2 0 1 3 4 6 7 8 9
</pre>
=={{header|FreeBASIC}}==
<lang freebasic>' version 03-12-2016
' compile with: fbc -s console
' for boundry checks on array's compile with: fbc -s console -exx

Sub selectionsort(arr() As Long)

' sort from lower bound to the highter bound
' array's can have subscript range from -2147483648 to +2147483647

Dim As Long i, j, x
Dim As Long lb = LBound(arr)
Dim As Long ub = UBound(arr)

For i = lb To ub -1
x = i
For j = i +1 To ub
If arr(j) < arr(x) Then x = j
Next
If x <> i Then
Swap arr(i), arr(x)
End If
Next

End Sub

' ------=< MAIN >=------

Dim As Long i, array(-7 To 7)
Dim As Long a = LBound(array), b = UBound(array)

Randomize Timer
For i = a To b : array(i) = i : Next
For i = a To b ' little shuffle
Swap array(i), array(Int(Rnd * (b - a +1)) + a)
Next

Print "unsort ";
For i = a To b : Print Using "####"; array(i); : Next : Print
selectionsort(array()) ' sort the array
Print " sort ";
For i = a To b : Print Using "####"; array(i); : Next : Print

' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End</lang>
{{out}}
<pre>unsort 1 -7 -5 -4 6 5 -3 4 2 0 3 -6 -2 7 -1
sort -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7</pre>

=={{header|GAP}}==
<lang gap>SelectionSort := function(v)
local i, j, k, n, m;
n := Size(v);
for i in [1 .. n] do
k := i;
m := v[i];
for j in [i + 1 .. n] do
if v[j] < m then
k := j;
m := v[j];
fi;
od;
v[k] := v[i];
v[i] := m;
od;
end;

v := List([1 .. 100], n -> Random([1 .. 100]));
SelectionSort(v);
v;</lang>

=={{header|Go}}==
<lang go>package main

import "fmt"

var a = []int{170, 45, 75, -90, -802, 24, 2, 66}

func main() {
fmt.Println("before:", a)
selectionSort(a)
fmt.Println("after: ", a)
}

func selectionSort(a []int) {
last := len(a) - 1
for i := 0; i < last; i++ {
aMin := a[i]
iMin := i
for j := i + 1; j < len(a); j++ {
if a[j] < aMin {
aMin = a[j]
iMin = j
}
}
a[i], a[iMin] = aMin, a[i]
}
}</lang>

More generic version that sorts anything that implements <code>sort.Interface</code>:
<lang go>package main

import (
"sort"
"fmt"
)

var a = []int{170, 45, 75, -90, -802, 24, 2, 66}

func main() {
fmt.Println("before:", a)
selectionSort(sort.IntSlice(a))
fmt.Println("after: ", a)
}

func selectionSort(a sort.Interface) {
last := a.Len() - 1
for i := 0; i < last; i++ {
iMin := i
for j := i + 1; j < a.Len(); j++ {
if a.Less(j, iMin) {
iMin = j
}
}
a.Swap(i, iMin)
}
}</lang>

=={{header|Haskell}}==
<lang haskell>import Data.List (delete)

selSort :: (Ord a) => [a] -> [a]
selSort [] = []
selSort xs = selSort (delete x xs) ++ [x]
where x = maximum xs</lang>

=={{header|Haxe}}==
<lang haxe>static function selectionSort(arr:Array<Int>) {
var len = arr.length;
for (index in 0...len)
{
var minIndex = index;
for (remainingIndex in (index+1)...len)
{
if (arr[minIndex] > arr[remainingIndex]) {
minIndex = remainingIndex;
}
}
if (index != minIndex) {
var temp = arr[index];
arr[index] = arr[minIndex];
arr[minIndex] = temp;
}
}
}</lang>

=={{header|Io}}==
<lang io>List do (
selectionSortInPlace := method(
size repeat(idx,
swapIndices(idx, indexOf(slice(idx, size) min))
)
)
)

l := list(-1, 4, 2, -9)
l selectionSortInPlace println # ==> list(-9, -1, 2, 4)</lang>

=={{header|Icon}} and {{header|Unicon}}==
<lang Icon>procedure main() #: demonstrate various ways to sort a list and string
demosort(selectionsort,[3, 14, 1, 5, 9, 2, 6, 3],"qwerty")
end


procedure selectionsort(X,op) #: return sorted list ascending(or descending)
local i,m

op := sortop(op,X) # select how and what we sort
every i := 1 to *X-1 do {
m := i
every j := i + 1 to *X do
if op(X[j],X[m]) then m := j # find X that belongs @i low (or high)
X[m ~= i] :=: X[m]
}
return X
end</lang>

Note: This example relies on [[Sorting_algorithms/Bubble_sort#Icon| the supporting procedures 'sortop', and 'demosort' in Bubble Sort]]. The full demosort exercises the named sort of a list with op = "numeric", "string", ">>" (lexically gt, descending),">" (numerically gt, descending), a custom comparator, and also a string.

{{out}} Abbreviated sample
<pre>Sorting Demo using procedure selectionsort
on list : [ 3 14 1 5 9 2 6 3 ]
with op = &null: [ 1 2 3 3 5 6 9 14 ] (0 ms)
...
on string : "qwerty"
with op = &null: "eqrtwy" (0 ms)</pre>

=={{header|J}}==
{{eff note|J|/:~}}
Create the following script and load it to a J session.
<lang j>selectionSort=: verb define
data=. y
for_xyz. y do.
temp=. xyz_index }. data
nvidx=. xyz_index + temp i. <./ temp
data=. ((xyz_index, nvidx) { data) (nvidx, xyz_index) } data
end.
data
)</lang>

In an email discussion, Roger_Hui presented the following tacit code:
<lang j>ix=: C.~ <@~.@(0, (i. <./))
ss1=: ({. , $:@}.)@ix^:(*@#)</lang>

To validate:
<lang j> [data=. 6 15 19 12 14 19 0 17 0 14
6 15 19 12 14 19 0 17 0 14
selectionSort data
0 0 6 12 14 14 15 17 19 19
ss1 data
0 0 6 12 14 14 15 17 19 19</lang>

=={{header|Java}}==
This algorithm sorts in place. The call <tt>sort(array)</tt> will rearrange the array and not create a new one.
<lang java>public static void sort(int[] nums){
for(int currentPlace = 0;currentPlace<nums.length-1;currentPlace++){
int smallest = Integer.MAX_VALUE;
int smallestAt = currentPlace+1;
for(int check = currentPlace; check<nums.length;check++){
if(nums[check]<smallest){
smallestAt = check;
smallest = nums[check];
}
}
int temp = nums[currentPlace];
nums[currentPlace] = nums[smallestAt];
nums[smallestAt] = temp;
}
}</lang>

=={{header|JavaScript}}==
This algorithm sorts array of numbers.
<lang javascript>function selectionSort(nums) {
var len = nums.length;
for(var i = 0; i < len; i++) {
var minAt = i;
for(var j = i + 1; j < len; j++) {
if(nums[j] < nums[minAt])
minAt = j;
}

if(minAt != i) {
var temp = nums[i];
nums[i] = nums[minAt];
nums[minAt] = temp;
}
}
return nums;
}</lang>

=={{header|jq}}==
The following implementation does not impose any restrictions on the types of entities that may appear in the array to be sorted. That is, the array may include any collection of JSON entities.

The definition also illustrates the use of an inner function (swap), and the use of jq's reduction operator, <tt>reduce</tt>.<lang jq># Sort any array
def selection_sort:
def swap(i;j): if i == j then . else .[i] as $tmp | .[i] = .[j] | .[j] = $tmp end;
length as $length
| reduce range(0; $length) as $currentPlace
# state: $array
( .;
. as $array
| (reduce range( $currentPlace; $length) as $check
# state: [ smallestAt, smallest] except initially [null]
( [$currentPlace+1] ;
if length == 1 or $array[$check] < .[1]
then [$check, $array[$check] ]
else .
end
)) as $ans
| swap( $currentPlace; $ans[0] )
) ;</lang>Example:<lang jq>
[1, 3.3, null, 2, null, [1,{"a":1 }] ] | selection_sort
</lang>
{{Out}}
<pre>
[
null,
null,
1,
2,
3.3,
[
1,
{
"a": 1
}
]
]
</pre>
=={{header|Julia}}==
Because this sort is liable to be used only when memory writes come at a high cost, I've implemented it as an in-place sort. By convention, Julia functions that alter their inputs have names ending in !, so this function is called <code>selectionsort!</code>.
<lang Julia>
function selectionsort!{T<:Real}(a::Array{T,1})
len = length(a)
if len < 2
return nothing
end
for i in 1:len-1
(lmin, j) = findmin(a[i+1:end])
if lmin < a[i]
a[i+j] = a[i]
a[i] = lmin
end
end
return nothing
end

a = [rand(-100:100) for i in 1:20]
println("Before Sort:")
println(a)
selectionsort!(a)
println("\nAfter Sort:")
println(a)
</lang>

{{out}}
<pre>
Before Sort:
[-15,-35,51,21,-11,12,-39,21,44,70,-16,85,55,-28,-52,83,-12,-20,37,-57]

After Sort:
[-57,-52,-39,-35,-28,-20,-16,-15,-12,-11,12,21,21,37,44,51,55,70,83,85]
</pre>

=={{header|Kotlin}}==
{{trans|C#}}
<lang scala>fun <T : Comparable<T>> Array<T>.selection_sort() {
for (i in 0..size - 2) {
var k = i
for (j in i + 1..size - 1)
if (this[j] < this[k])
k = j

if (k != i) {
val tmp = this[i]
this[i] = this[k]
this[k] = tmp
}
}
}

fun main(args: Array<String>) {
val i = arrayOf(4, 9, 3, -2, 0, 7, -5, 1, 6, 8)
i.selection_sort()
println(i.joinToString())

val s = Array(i.size, { -i[it].toShort() })
s.selection_sort()
println(s.joinToString())

val c = arrayOf('z', 'h', 'd', 'c', 'a')
c.selection_sort()
println(c.joinToString())
}</lang>
{{out}}
<pre>-5, -2, 0, 1, 3, 4, 6, 7, 8, 9
-9, -8, -7, -6, -4, -3, -1, 0, 2, 5
a, c, d, h, z</pre>

=={{header|Liberty BASIC}}==
<lang lb> itemCount = 20
dim A(itemCount)
for i = 1 to itemCount
A(i) = int(rnd(1) * 100)
next i

print "Before Sort"
gosub [printArray]

'--- Selection sort algorithm
for i = 1 to itemCount-1
jMin = i
for j = i+1 to itemCount
if A(j) < A(jMin) then jMin = j
next
tmp = A(i)
A(i) = A(jMin)
A(jMin) = tmp
next
'--- end of (Selection sort algorithm)

print "After Sort"
gosub [printArray]
end

[printArray]
for i = 1 to itemCount
print using("###", A(i));
next i
print
return
</lang>

=={{header|Lua}}==
<lang lua>function SelectionSort( f )
for k = 1, #f-1 do
local idx = k
for i = k+1, #f do
if f[i] < f[idx] then
idx = i
end
end
f[k], f[idx] = f[idx], f[k]
end
end


f = { 15, -3, 0, -1, 5, 4, 5, 20, -8 }

SelectionSort( f )

for i in next, f do
print( f[i] )
end</lang>

=={{header|Mathematica}}==
Procedural solution with custom min function:

<lang Mathematica>SelectSort[x_List] := Module[{n = 1, temp, xi = x, j},
While[n <= Length@x,
temp = xi[[n]];
For[j = n, j <= Length@x, j++,
If[xi[[j]] < temp, temp = xi[[j]]];
];
xi[[n ;;]] = {temp}~Join~
Delete[xi[[n ;;]], First@Position[xi[[n ;;]], temp] ];
n++;
];
xi
]</lang>

Recursive solution using a pre-existing Min[] function:

<lang Mathematica>SelectSort2[x_List]:= Flatten[{Min@x, If[Length@x > 1, SelectSort2@Drop[x, First@Position[x, Min@x]], {}] }];</lang>

Validate by testing the ordering of a random number of randomly-sized random lists:

<lang Mathematica>{And @@ Table[l = RandomInteger[150, RandomInteger[1000]];
Through[And[Length@# == Length@SelectSort@# &, OrderedQ@SelectSort@# &]@l],
{RandomInteger[150]}],
Block[{$RecursionLimit = Infinity},
And @@ Table[l = RandomInteger[150, RandomInteger[1000]];
Through[And[Length@# == Length@SelectSort2@# &, OrderedQ@SelectSort2@# &]@l],
{RandomInteger[150]}]
]}</lang>

Validation Result:
<pre>{True, True}</pre>

=={{header|MATLAB}} / {{header|Octave}}==

<lang MATLAB>function list = selectionSort(list)

listSize = numel(list);
for i = (1:listSize-1)

minElem = list(i);
minIndex = i;
%This for loop can be vectorized, but there will be no significant
%increase in sorting efficiency.
for j = (i:listSize)
if list(j) <= minElem
minElem = list(j);
minIndex = j;
end
end
if i ~= minIndex
list([minIndex i]) = list([i minIndex]); %Swap
end
end %for
end %selectionSort</lang>

Sample Usage:
<lang MATLAB>>> selectionSort([4 3 1 5 6 2])

ans =

1 2 3 4 5 6</lang>

=={{header|Maxima}}==
<lang maxima>selection_sort(v) := block([k, m, n],
n: length(v),
for i: 1 thru n do (
k: i,
m: v[i],
for j: i + 1 thru n do
if v[j] < m then (k: j, m: v[j]),
v[k]: v[i],
v[i]: m
))$

v: makelist(random(199) - 99, i, 1, 10); /* [52, -85, 41, -70, -59, 88, 19, 80, 90, 44] */
selection_sort(v)$
v; /* [-85, -70, -59, 19, 41, 44, 52, 80, 88, 90] */</lang>

=={{header|MAXScript}}==
<lang maxscript>fn selectionSort arr =
(
local min = undefined
for i in 1 to arr.count do
(
min = i
for j in i+1 to arr.count do
(
if arr[j] < arr[min] then
(
min = j
)
)
swap arr[i] arr[min]
)
arr
)

data = selectionSort #(4, 9, 3, -2, 0, 7, -5, 1, 6, 8)
print data</lang>

=={{header|Nemerle}}==
{{trans|C#}}
<lang Nemerle>using System;
using System.Console;

module Selection
{
public static Sort[T](this a : array[T]) : void
where T : IComparable
{
mutable k = 0;
def lastindex = a.Length - 1;
foreach (i in [0 .. lastindex])
{
k = i;
foreach (j in [i .. lastindex])
when (a[j].CompareTo(a[k]) < 0) k = j;
a[i] <-> a[k];
}
}
Main() : void
{
def arr = array[6, 2, 8, 3, 9, 4, 7, 3, 9, 1];
arr.Sort();
foreach (i in arr) Write($"$i ");
}
}</lang>

=={{header|NetRexx}}==
<lang NetRexx>/* NetRexx */
options replace format comments java crossref savelog symbols binary

import java.util.List

placesList = [String -
"UK London", "US New York", "US Boston", "US Washington" -
, "UK Washington", "US Birmingham", "UK Birmingham", "UK Boston" -
]

lists = [ -
placesList -
, selectionSort(String[] Arrays.copyOf(placesList, placesList.length)) -
]

loop ln = 0 to lists.length - 1
cl = lists[ln]
loop ct = 0 to cl.length - 1
say cl[ct]
end ct
say
end ln

return

method selectionSort(a = String[]) public constant binary returns String[]

rl = String[a.length]
al = List selectionSort(Arrays.asList(a))
al.toArray(rl)

return rl

method selectionSort(a = List) public constant binary returns ArrayList

ra = ArrayList(a)
n = ra.size

iPos = int
iMin = int

loop iPos = 0 to n - 1
iMin = iPos
loop i_ = iPos + 1 to n - 1
if (Comparable ra.get(i_)).compareTo(Comparable ra.get(iMin)) < 0 then do
iMin = i_
end
end i_
if iMin \= iPos then do
swap = ra.get(iPos)
ra.set(iPos, ra.get(iMin))
ra.set(iMin, swap)
end
end iPos

return ra
</lang>
{{out}}
<pre>
UK London
US New York
US Boston
US Washington
UK Washington
US Birmingham
UK Birmingham
UK Boston

UK Birmingham
UK Boston
UK London
UK Washington
US Birmingham
US Boston
US New York
US Washington
</pre>

=={{header|Nim}}==
<lang nim>proc selectionSort[T](a: var openarray[T]) =
let n = a.len
for i in 0 .. <n:
var m = i
for j in i .. <n:
if a[j] < a[m]:
m = j
swap a[i], a[m]

var a = @[4, 65, 2, -31, 0, 99, 2, 83, 782]
selectionSort a
echo a</lang>
{{out}}
<pre>@[-31, 0, 2, 2, 4, 65, 83, 99, 782]</pre>

=={{header|OCaml}}==
<lang ocaml>let rec selection_sort = function
[] -> []
| first::lst ->
let rec select_r small output = function
[] -> small :: selection_sort output
| x::xs when x < small -> select_r x (small::output) xs
| x::xs -> select_r small (x::output) xs
in
select_r first [] lst</lang>

=={{header|Oforth}}==

<lang Oforth>: selectSort(l)
| b j i k s |
l size ->s
l asListBuffer ->b

s loop: i [
i dup ->k b at
i 1 + s for: j [ b at(j) 2dup <= ifTrue: [ drop ] else: [ nip j ->k ] ]
k i b at b put i swap b put
]
b dup freeze ;</lang>

=={{header|ooRexx}}==

<lang oorexx>/*REXX ****************************************************************
* program sorts an array using the selection-sort method.
* derived from REXX solution
* Note that ooRexx can process Elements of the stem argument (Use Arg)
* 06.10.2010 Walter Pachl
**********************************************************************/
call generate /*generate the array elements. */
call show 'before sort' /*show the before array elements,*/
call selectionSort x. /*invoke the selection sort. */
call show 'after sort' /*show the after array elements.*/
exit /*stick a fork in it, we're done.*/

selectionSort: Procedure
Use Arg s. /* gain access to the argument */
do j=1 To s.0-1
t=s.j;
p=j;
do k=j+1 to s.0
if s.k<t then do;
t=s.k;
p=k;
end
end
if p=j then
iterate
t=s.j;
s.j=s.p;
s.p=t
end
return

show:
Parse Arg heading
Say heading
Do i=1 To x.0
Say i' 'x.i
End
say copies('-',79)
Return
return

generate:
x.1='---The seven hills of Rome:---'
x.2='=============================='
x.3='Caelian'
x.4='Palatine'
x.5='Capitoline'
x.6='Virminal'
x.7='Esquiline'
x.8='Quirinal'
x.9='Aventine'
x.0=9
return</lang>

=={{header|Oz}}==
Although lists are much more used in Oz than arrays, this algorithm seems more natural for arrays.
<lang oz>declare
proc {SelectionSort Arr}
proc {Swap K L}
Arr.K := (Arr.L := Arr.K)
end
Low = {Array.low Arr}
High = {Array.high Arr}
in
%% for every index I of the array
for I in Low..High do
%% find the index of the minimum element
%% with an index >= I
Min = {NewCell Arr.I}
MinIndex = {NewCell I}
in
for J in I..High do
if Arr.J < @Min then
Min := Arr.J
MinIndex := J
end
end
%% and put that minimum element to the left
{Swap @MinIndex I}
end
end
A = {Tuple.toArray unit(3 1 4 1 5 9 2 6 5)}
in
{SelectionSort A}
{Show {Array.toRecord unit A}}</lang>

=={{header|PARI/GP}}==
<lang parigp>selectionSort(v)={
for(i=1,#v-1,
my(mn=i,t);
for(j=i+1,#v,
if(v[j]<v[mn],mn=j)
);
t=v[mn];
v[mn]=v[i];
v[i]=t
);
v
};</lang>

=={{header|Pascal}}==
See [[Sorting_algorithms/Selection_sort#Delphi | Delphi]]

=={{header|Perl}}==
{{trans|Tcl}}
<lang perl>sub selection_sort
{my @a = @_;
foreach my $i (0 .. $#a - 1)
{my $min = $i + 1;
$a[$_] < $a[$min] and $min = $_ foreach $min .. $#a;
$a[$i] > $a[$min] and @a[$i, $min] = @a[$min, $i];}
return @a;}</lang>

=={{header|Perl 6}}==
Solution 1:
<lang perl6>sub selection_sort ( @a is copy ) {
for 0 ..^ @a.end -> $i {
my $min = [ $i+1 .. @a.end ].min: { @a[$_] };
@a[$i, $min] = @a[$min, $i] if @a[$i] > @a[$min];
}
return @a;
}

my @data = 22, 7, 2, -5, 8, 4;
say 'input = ' ~ @data;
say 'output = ' ~ @data.&selection_sort;
</lang>

{{out}}
<pre>input = 22 7 2 -5 8 4
output = -5 2 4 7 8 22
</pre>

Solution 2:
<lang perl6>sub selectionSort(@tmp) {
for ^@tmp -> $i {
my $min = $i; @tmp[$i, $_] = @tmp[$_, $i] if @tmp[$min] > @tmp[$_] for $i^..^@tmp;
}
return @tmp;
}
</lang>

{{out}}
<pre>input = 22 7 2 -5 8 4
output = -5 2 4 7 8 22
</pre>

=={{header|Phix}}==
Copy of [[Sorting_algorithms/Selection_sort#Euphoria|Euphoria]]
<lang Phix>function selection_sort(sequence s)
integer m
for i=1 to length(s) do
m = i
for j=i+1 to length(s) do
if s[j]<s[m] then
m = j
end if
end for
{s[i],s[m]} = {s[m],s[i]}
end for
return s
end function</lang>

=={{header|PHP}}==
Iterative:
<lang php>function selection_sort(&$arr) {
$n = count($arr);
for($i = 0; $i < count($arr); $i++) {
$min = $i;
for($j = $i + 1; $j < $n; $j++){
if($arr[$j] < $arr[$min]){
$min = $j;
}
}
list($arr[$i],$arr[$min]) = array($arr[$min],$arr[$i]);
}
}</lang>
Recursive:
<lang php>function selectionsort($arr,$result=array()){
if(count($arr) == 0){
return $result;
}
$nresult = $result;
$nresult[] = min($arr);
unset($arr[array_search(min($arr),$arr)]);
return selectionsort($arr,$nresult);
}</lang>

=={{header|PicoLisp}}==
<lang PicoLisp>(de selectionSort (Lst)
(map
'((L) (and (cdr L) (xchg L (member (apply min @) L))))
Lst )
Lst )</lang>

=={{header|PL/I}}==
<lang PL/I>
Selection: procedure options (main); /* 2 November 2013 */

declare a(10) fixed binary initial (
5, 7, 3, 98, 4, -3, 25, 20, 60, 17);

put edit (trim(a)) (a, x(1));

call Selection_Sort (a);

put skip edit (trim(a)) (a, x(1));

Selection_sort: procedure (a);
declare a(*) fixed binary;
declare t fixed binary;
declare n fixed binary;
declare (i, j, k) fixed binary;

n = hbound(a,1);
do j = 1 to n;
k = j; t = a(j);
do i = j+1 to n;
if t > a(i) then do; t = a(i); k = i; end;
end;
a(k) = a(j); a(j) = t;
end;
end Selection_Sort;

end Selection;
</lang>
Results:
<pre>
5 7 3 98 4 -3 25 20 60 17
-3 3 4 5 7 17 20 25 60 98
</pre>

=={{header|PowerShell}}==
<lang PowerShell>Function SelectionSort( [Array] $data )
{
$datal=$data.length-1
0..( $datal - 1 ) | ForEach-Object {
$min = $data[ $_ ]
$mini = $_
( $_ + 1 )..$datal | ForEach-Object {
if( $data[ $_ ] -lt $min ) {
$min = $data[ $_ ]
$mini = $_
}
}
$temp = $data[ $_ ]
$data[ $_ ] = $min
$data[ $mini ] = $temp
}
$data
}

$l = 100; SelectionSort( ( 1..$l | ForEach-Object { $Rand = New-Object Random }{ $Rand.Next( 0, $l - 1 ) } ) )</lang>

=={{header|Prolog}}==
Works with '''SWI-Prolog 6.3.11''' (needs nth0/4).
<lang Prolog>
selection_sort([], []).
selection_sort([H | L], [H1 | L2]) :-
exchange(H, L, H1, L1),
selection_sort(L1, L2).


exchange(H, [], H, []).

exchange(H, L, H1, L1) :-
min_list(L, H2),
( H < H2
-> H1 = H, L1 = L
; H1 = H2,
% does the exchange of the number H
% and the min of the list
nth0(Ind, L, H1, L2),
nth0(Ind, L1, H, L2)).
</lang>
=={{header|PureBasic}}==
<lang PureBasic>Procedure selectionSort(Array a(1))
Protected i, j, lastIndex, minIndex
lastIndex = ArraySize(a())
For i = 0 To lastIndex - 1
minIndex = i
For j = i + 1 To lastIndex
If a(minIndex) > a(j)
minIndex = j
EndIf
Next
Swap a(minIndex), a(i)
Next
EndProcedure</lang>

=={{header|Python}}==

<lang python>def selection_sort(lst):
for i, e in enumerate(lst):
mn = min(range(i,len(lst)), key=lst.__getitem__)
lst[i], lst[mn] = lst[mn], e
return lst</lang>

=={{header|R}}==
For loop:
<lang r>selectionsort.loop <- function(x)
{
lenx <- length(x)
for(i in seq_along(x))
{
mini <- (i - 1) + which.min(x[i:lenx])
start_ <- seq_len(i-1)
x <- c(x[start_], x[mini], x[-c(start_, mini)])
}
x
}</lang>
Recursive:

(A prettier solution, but, you may need to increase the value of options("expressions") to test it. Also, you may get a stack overflow if the length of the input vector is more than a few thousand.)
<lang r>selectionsort.rec <- function(x)
{
if(length(x) > 1)
{
mini <- which.min(x)
c(x[mini], selectionsort(x[-mini]))
} else x
}</lang>

=={{header|Qi}}==
{{trans|sml}}
<lang qi>(define select-r
Small [] Output -> [Small | (selection-sort Output)]
Small [X|Xs] Output -> (select-r X Xs [Small|Output]) where (< X Small)
Small [X|Xs] Output -> (select-r Small Xs [X|Output]))

(define selection-sort
[] -> []
[First|Lst] -> (select-r First Lst []))

(selection-sort [8 7 4 3 2 0 9 1 5 6])
</lang>

=={{header|Racket}}==
<lang racket>
#lang racket
(define (selection-sort xs)
(cond [(empty? xs) '()]
[else (define x0 (apply min xs))
(cons x0 (selection-sort (remove x0 xs)))]))
</lang>

=={{header|Ra}}==
<lang Ra>
class SelectionSort
**Sort a list with the Selection Sort algorithm**
on start
args := program arguments
.sort(args)
print args
define sort(list) is shared
**Sort the list**
test
list := [4, 2, 7, 3]
.sort(list)
assert list = [2, 3, 4, 7]
body
count := list.count
last := count - 1
for i in last
minCandidate := i
j := i + 1
while j < count
if list[j] < list[minCandidate], minCandidate := j
j :+ 1
temp := list[i]
list[i] := list[minCandidate]
list[minCandidate] := temp
</lang>

=={{header|REXX}}==
<lang rexx>/*REXX program sorts a stemmed array using the selection-sort algorithm. */
@.=; @.1 = '---The seven hills of Rome:---'
@.2 = '=============================='
@.3 = 'Caelian'
@.4 = 'Palatine'
@.5 = 'Capitoline'
@.6 = 'Virminal'
@.7 = 'Esquiline'
@.8 = 'Quirinal'
@.9 = 'Aventine'
do #=1 until @.#==''; end; #=#-1 /*find the number of items in the array*/
/* [↑] adjust # ('cause of DO index)*/
call show 'before sort' /*show the before array elements. */
say copies('▒', 65) /*show a nice separator line (fence). */
call selectionSort # /*invoke selection sort (and # items). */
call show ' after sort' /*show the after array elements. */
exit /*stick a fork in it, we're a;; done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
selectionSort: procedure expose @.; parse arg n
do j=1 for n-1
_=@.j; p=j; do k=j+1 to n
if @.k<_ then do; _=@.k; p=k; end
end /*k*/
if p==j then iterate /*if the same, the order of items OK. */
_=@.j; @.j=@.p; @.p=_ /*swap 2 items that're out-of-sequence.*/
end /*j*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
show: do i=1 for #; say ' element' right(i,length(#)) arg(1)":" @.i; end; return</lang>
'''output'''
<pre>
element 1 before sort: ---The seven hills of Rome:---
element 2 before sort: ==============================
element 3 before sort: Caelian
element 4 before sort: Palatine
element 5 before sort: Capitoline
element 6 before sort: Virminal
element 7 before sort: Esquiline
element 8 before sort: Quirinal
element 9 before sort: Aventine
▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒
element 1 after sort: ---The seven hills of Rome:---
element 2 after sort: ==============================
element 3 after sort: Aventine
element 4 after sort: Caelian
element 5 after sort: Capitoline
element 6 after sort: Esquiline
element 7 after sort: Palatine
element 8 after sort: Quirinal
element 9 after sort: Virminal
</pre>

=={{header|Ring}}==
<lang ring>
aList = [7,6,5,9,8,4,3,1,2,0]
see sortList(aList)

func sortList list
count = len(list) + 1
last = count - 1
for i = 1 to last
minCandidate = i
j = i + 1
while j < count
if list[j] < list[minCandidate] minCandidate = j ok
j = j + 1
end
temp = list[i]
list[i] = list[minCandidate]
list[minCandidate] = temp
next
return list
</lang>

=={{header|Ruby}}==
{{trans|Tcl}}
<lang ruby>class Array
def selectionsort!
for i in 0..length-2
min_idx = i
for j in (i+1)...length
min_idx = j if self[j] < self[min_idx]
end
self[i], self[min_idx] = self[min_idx], self[i]
end
self
end
end
ary = [7,6,5,9,8,4,3,1,2,0]
p ary.selectionsort!
# => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]</lang>

=={{header|Run BASIC}}==
<lang runbasic>siz = 10
dim srdData(siz)
for i = 1 to siz
srtData(i) = rnd(0) * 100
next i

FOR i = 1 TO siz-1
lo = i
FOR j = (i + 1) TO siz
IF srtData(j) < srtData(lo) lo = j
NEXT j
if i <> lo then
temp = srtData(i)
srtData(i) = srtData(lo)
srtData(lo) = temp
end if
NEXT i

for i = 1 to siz
print i;chr$(9);srtData(i)
next i</lang>
<pre>1 20.5576419
2 32.4299311
3 48.345375
4 54.135847
5 63.1427764
6 67.8079128
7 85.2134895
8 91.3576602
9 95.4280853
10 98.8323211</pre>

=={{header|Scala}}==
<lang scala>def swap(a: Array[Int], i1: Int, i2: Int) = { val tmp = a(i1); a(i1) = a(i2); a(i2) = tmp }

def selectionSort(a: Array[Int]) =
for (i <- 0 until a.size - 1)
swap(a, i, (i + 1 until a.size).foldLeft(i)((currMin, index) =>
if (a(index) < a(currMin)) index else currMin))</lang>

This version avoids the extra definition by using a function literal:

<lang scala>def selectionSort(a: Array[Int]) = for (i <- 0 until a.size - 1) (
{ (i1: Int, i2: Int) => val tmp = a(i1); a(i1) = a(i2); a(i2) = tmp }
) (i, (i + 1 until a.size).foldLeft(i)((currMin, index) => if (a(index) < a(currMin)) index else currMin) )</lang>

Functional way:
<lang scala>def selectionSort[T <% Ordered[T]](list: List[T]): List[T] = {
def remove(e: T, list: List[T]): List[T] =
list match {
case Nil => Nil
case x :: xs if x == e => xs
case x :: xs => x :: remove(e, xs)
}

list match {
case Nil => Nil
case _ =>
val min = list.min
min :: selectionSort(remove(min, list))
}
}
</lang>

=={{header|Seed7}}==
<lang seed7>const proc: selectionSort (inout array elemType: arr) is func
local
var integer: i is 0;
var integer: j is 0;
var integer: min is 0;
var elemType: help is elemType.value;
begin
for i range 1 to length(arr) - 1 do
min := i;
for j range i + 1 to length(arr) do
if arr[j] < arr[min] then
min := j;
end if;
end for;
help := arr[min];
arr[min] := arr[i];
arr[i] := help;
end for;
end func;</lang>

Original source: [http://seed7.sourceforge.net/algorith/sorting.htm#selectionSort]

=={{header|Sidef}}==
{{trans|Ruby}}
<lang ruby>class Array {
method selectionsort {
for i in ^(self.end) {
var min_idx = i
for j in (i+1 .. self.end) {
if (self[j] < self[min_idx]) {
min_idx = j
}
}
self.swap(i, min_idx)
}
return self
}
}

var nums = [7,6,5,9,8,4,3,1,2,0];
say nums.selectionsort;

var strs = ["John", "Kate", "Zerg", "Alice", "Joe", "Jane"];
say strs.selectionsort;</lang>

=={{header|Standard ML}}==
<lang sml>fun selection_sort [] = []
| selection_sort (first::lst) =
let
val (small, output) = foldl
(fn (x, (small, output)) =>
if x < small then
(x, small::output)
else
(small, x::output)
) (first, []) lst
in
small :: selection_sort output
end</lang>
=={{header|Swift}}==
<lang Swift>func selectionSort(inout arr:[Int]) {
var min:Int
for n in 0..<arr.count {
min = n
for x in n+1..<arr.count {
if (arr[x] < arr[min]) {
min = x
}
}
if min != n {
let temp = arr[min]
arr[min] = arr[n]
arr[n] = temp
}
}
}</lang>

=={{header|Tcl}}==
{{tcllib|struct::list}}
<lang tcl>package require Tcl 8.5
package require struct::list

proc selectionsort {A} {
set len [llength $A]
for {set i 0} {$i < $len - 1} {incr i} {
set min_idx [expr {$i + 1}]
for {set j $min_idx} {$j < $len} {incr j} {
if {[lindex $A $j] < [lindex $A $min_idx]} {
set min_idx $j
}
}
if {[lindex $A $i] > [lindex $A $min_idx]} {
struct::list swap A $i $min_idx
}
}
return $A
}

puts [selectionsort {8 6 4 2 1 3 5 7 9}] ;# => 1 2 3 4 5 6 7 8 9</lang>

=={{header|TI-83 BASIC}}==
Store input into L<sub>1</sub> and prgmSORTSLCT will store the sorted output into L<sub>2</sub>.
:L<sub>1</sub>→L<sub>2</sub>
:dim(L<sub>2</sub>)→I
:For(A,1,I)
:A→C
:0→X
:For(B,A,I)
:If L<sub>2</sub>(B)<L<sub>2</sub>(C)
:Then
:B→C
:1→X
:End
:End
:If X=1
:Then
:L<sub>2</sub>(C)→B
:L<sub>2</sub>(A)→L<sub>2</sub>(C)
:B→L<sub>2</sub>(A)
:End
:End
:DelVar A
:DelVar B
:DelVar C
:DelVar I
:DelVar X
:Return

=={{header|uBasic/4tH}}==
<lang>PRINT "Selection sort:"
n = FUNC (_InitArray)
PROC _ShowArray (n)
PROC _Selectionsort (n)
PROC _ShowArray (n)
PRINT
END


_Selectionsort PARAM (1) ' Selection sort
LOCAL (3)

FOR b@ = 0 TO a@-1
c@ = b@

FOR d@ = b@ TO a@-1
IF @(d@) < @(c@) THEN c@ = d@
NEXT

IF b@ # c@ THEN PROC _Swap (b@, c@)
NEXT
RETURN
_Swap PARAM(2) ' Swap two array elements
PUSH @(a@)
@(a@) = @(b@)
@(b@) = POP()
RETURN
_InitArray ' Init example array
PUSH 4, 65, 2, -31, 0, 99, 2, 83, 782, 1
FOR i = 0 TO 9
@(i) = POP()
NEXT
RETURN (i)
_ShowArray PARAM (1) ' Show array subroutine
FOR i = 0 TO a@-1
PRINT @(i),
NEXT
PRINT
RETURN</lang>
=={{header|Ursala}}==
The selection_sort function is parameterized by a relational predicate p.
There are no arrays in Ursala so it uses a list, and the selected item
is deleted from the list and inserted into another on each iteration
rather than swapped with a preceding item of the same list.
<lang Ursala>#import std

selection_sort "p" = @iNX ~&l->rx ^(gldif ==,~&r)^/~&l ^|C/"p"$- ~&</lang>
This is already a bad way to code a sorting algorithm in this
language, but with only a bit more work, we can get a bigger and
slower version that more closely simulates the operations of
repeatedly reordering an array.
<lang Ursala>selection_sort "p" = ~&itB^?a\~&a ^|JahPfatPRC/~& ~=-~BrhPltPClhPrtPCTlrTQrS^D/"p"$- ~&</lang>
Here is a test program sorting by the partial order relation on natural
numbers.
<lang Ursala>#import nat
#cast %nL

example = selection_sort(nleq) <294,263,240,473,596,392,621,348,220,815></lang>
{{out}}
<pre><220,240,263,294,348,392,473,596,621,815></pre>

=={{header|VBA}}==
I shameless stole the swap function from the bubblesort VBscript implementation.

<lang VBA>
sub swap( byref a, byref b)
dim tmp
tmp = a
a = b
b = tmp
end sub

function selectionSort (a)
for i = 0 to ubound(a)
k = i
for j=i+1 to ubound(a)
if a(j) < a(i) then
swap a(i), a(j)
end if
next
next
selectionSort = a
end function
</lang>
=={{header|VBScript}}==
<lang vb>Function Selection_Sort(s)
arr = Split(s,",")
For i = 0 To UBound(arr)
For j = i To UBound(arr)
temp = arr(i)
If arr(j) < arr(i) Then
arr(i) = arr(j)
arr(j) = temp
End If
Next
Next
Selection_Sort = (Join(arr,","))
End Function

WScript.StdOut.Write "Pre-Sort" & vbTab & "Sorted"
WScript.StdOut.WriteLine
WScript.StdOut.Write "3,2,5,4,1" & vbTab & Selection_Sort("3,2,5,4,1")
WScript.StdOut.WriteLine
WScript.StdOut.Write "c,e,b,a,d" & vbTab & Selection_Sort("c,e,b,a,d")</lang>
{{out}}
<pre>
Pre-Sort Sorted
3,2,5,4,1 1,2,3,4,5
c,e,b,a,d a,b,c,d,e
</pre>

=={{header|XPL0}}==
<lang XPL0>include c:\cxpl\codes; \intrinsic 'code' declarations
string 0; \use zero-terminated strings

proc SelSort(A, N); \Selection sort
char A; \address of array
int N; \number of elements in array (size)
int I, J, S, JS, T;
[for I:= 0 to N-2 do
[S:= (~0)>>1;
for J:= I to N-1 do \find smallest element
if A(J) < S then [S:= A(J); JS:= J];
T:= A(I); A(I):= A(JS); A(JS):= T;
];
];

func StrLen(Str); \Return number of characters in an ASCIIZ string
char Str;
int I;
for I:= 0 to -1>>1-1 do
if Str(I) = 0 then return I;

char Str;
[Str:= "Pack my box with five dozen liquor jugs.";
SelSort(Str, StrLen(Str));
Text(0, Str); CrLf(0);
]</lang>

{{out}}
<pre>
.Pabcdeefghiiijklmnoooqrstuuvwxyz
</pre>

=={{header|zkl}}==
<lang zkl>fcn selectionSort(list){ // sort a list of ints
copy,r:=list.copy(),List();
while(copy){
min,idx:=(0).min(copy), copy.find(min);
r.append(min);
copy.del(idx);
}
r
}</lang>
<lang zkl>selectionSort(List(28, 44, 46, 24, 19, -5, 2, 17, 11, 25, 4)).println();</lang>
{{out}}
<pre>
L(-5,2,4,11,17,19,24,25,28,44,46)
</pre>


{{omit from|GUISS}}

Revision as of 11:22, 15 January 2017

-module(solution). -import(lists,[delete/2,max/1]). -compile(export_all). selection_sort([],Sort)-> Sort; selection_sort(Ar,Sort)-> M=max(Ar), Ad=delete(M,Ar), selection_sort(Ad,[M|Sort]). print_array([])->ok; print_array([H|T])-> io:format("~p~n",[H]), print_array(T).

main()-> Ans=selection_sort([1,5,7,8,4,10],[]), print_array(Ans).

Retrieved from "https://rosettacode.org/wiki/Sorting_algorithms/Selection_sort?oldid=88652"