# Repeat a string

Repeat a string
You are encouraged to solve this task according to the task description, using any language you may know.

Take a string and repeat it some number of times.

Example: repeat("ha", 5)   =>   "hahahahaha"

If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****").

print(‘ha’ * 5)
Output:
hahahahaha

## 360 Assembly

*        Repeat a string           - 19/04/2020
REPEATS  CSECT
USING  REPEATS,R13        base register
B      72(R15)            skip savearea
DC     17F'0'             savearea
SAVE   (14,12)            save previous context
ST     R13,4(R15)         link backward
ST     R15,8(R13)         link forward
LR     R13,R15            set addressability
XPRNT  C24,24             print c24
LA     R1,PARMLST         pg=repeat(cx,ii) - repeat('abc ',6)
BAL    R14,REPEAT         call repeat
XPRNT  PG,L'PG            print pg
L      R13,4(0,R13)       restore previous savearea pointer
RETURN (14,12),RC=0       restore registers from calling save
REPEAT   CNOP   0,4                procedure repeat(b,a,i)
STM    R2,R8,REPEATSA     save registers
L      R2,0(R1)           @b=%r1
L      R3,4(R1)           @a=%(r1+4)
L      R4,8(R1)           @i=%(r1+8)
LR     R5,R3              length(a) before a
SH     R5,=H'2'           @lengh(a)
LH     R6,0(R5)           l=length(a)
LR     R7,R6              l
BCTR   R7,0               l-1
L      R8,0(R4)           i=%r4
LTR    R8,R8              if i<=0
BNP    RET                then return
LOOP     EX     R7,MVCX            move a to b len R6
AR     R2,R6              @b+=l
BCT    R8,LOOP            loop i times
RET      LM     R2,R8,REPEATSA     restore registers
BR     R14                return
PARMLST  DC     A(PG,CX,II)        parmlist
REPEATSA DS     7F                 local savearea
MVCX     MVC    0(0,R2),0(R3)      move @ R3 to @ R2
C24      DC     6C'xyz '           constant repeat - repeat('xyz ',6)
LCX      DC     AL2(L'CX)          lengh(cc)
CX       DC     CL4'abc '          cx
II       DC     F'6'               ii
PG       DC     CL80' '            pg
REGEQU
END    REPEATS
Output:
xyz xyz xyz xyz xyz xyz
abc abc abc abc abc abc

## 4DOS Batch

gosub repeat ha 5
echo %@repeat[*,5]
quit

:Repeat [String Times]
do %Times%
echos %String%
enddo
echo.
return

Output shows:

hahahahaha
*****

## 6502 Assembly

CHROUT equ \$FFD2    ;KERNAL call, prints the accumulator to the screen as an ascii value.

org \$0801

db \$0E,\$08,\$0A,\$00,\$9E,\$20,\$28,\$32,\$30,\$36,\$34,\$29,\$00,\$00,\$00

lda #>TestStr
sta \$11

lda #<TestStr
sta \$10

ldx #5				;number of times to repeat

loop:
jsr PrintString
dex
bne loop

RTS					;RETURN TO BASIC

PrintString:
ldy #0
loop_PrintString:
lda (\$10),y			;this doesn't actually increment the pointer itself, so we don't need to back it up.
beq donePrinting
jsr CHROUT
iny
jmp loop_PrintString
donePrinting:
rts

TestStr:
db "HA",0
Output:
READY.
LOAD"*",8,1:

SEARCHING FOR *
LOADING
READY.
RUN
HAHAHAHAHA
READY.

## 68000 Assembly

Easiest way to do this is with a loop.

MOVE.W #5-1,D1
RepString:
LEA A3, MyString
MOVE.L A3,-(SP) ;PUSH A3
JSR PrintString ;unimplemented hardware-dependent printing routine, assumed to not clobber D1
MOVE.L (SP)+,A3 ;POP A3
DBRA D1,RepString
RTS             ;return to basic or whatever

MyString:
DC.B "ha",0
even

"ha" 5 s:*
. cr

Output shows:

hahahahaha

## ABAP

This works for ABAP Version 7.40 and above

report z_repeat_string.

write repeat( val = `ha`  occ = 5 ).
Output:
hahahahaha

## Action!

Proc Main()
byte REPEAT

REPEAT=5
Do
Print("ha")
REPEAT==-1
Until REPEAT=0
Do

Return
Output:
hahahahaha

## ActionScript

ActionScript does not have a built-in way to repeat a string multiple times, but the addition operator can be used to concatenate strings.

In Flex, there is the method mx.utils.StringUtil.repeat().

### Iterative version

function repeatString(string:String, numTimes:uint):String
{
var output:String = "";
for(var i:uint = 0; i < numTimes; i++)
output += string;
return output;
}

### Recursive version

The following double-and-add method is much faster when repeating a string many times.

function repeatRecursive(string:String, numTimes:uint):String
{
if(numTimes == 0) return "";
if(numTimes & 1) return string + repeatRecursive(string, numTimes - 1);
var tmp:String = repeatRecursive(string, numTimes/2);
return tmp + tmp;
}

### Flex

import mx.utils.StringUtil;
trace(StringUtil.repeat("ha", 5));

Sample Output:

hahahahaha

## Ada

In Ada multiplication of an universal integer to string gives the desired result. Here is an example of use:

with Ada.Strings.Fixed;  use Ada.Strings.Fixed;
with Ada.Text_IO;        use Ada.Text_IO;

procedure String_Multiplication is
begin
Put_Line (5 * "ha");
end String_Multiplication;

Sample output:

hahahahaha

## Aime

call_n(5, o_text, "ha");

print (5 * "ha")

## Amazing Hopper

#!/usr/bin/hopper
#include <hopper.h>

main:
{"ha"}replyby(5),    println
{"ha",5}replicate,   println
{0}return
hahahahaha
hahahahaha

## APL

Fill up a string of length 10 with 'ha':

10'ha'
hahahahaha

Alternatively, define a function:

REPEAT{(×⍴)}
5 REPEAT 'ha'
hahahahaha

## AppleScript

set str to "ha"
set final_string to ""
repeat 5 times
set final_string to final_string & str
end repeat

For larger numbers of repetitions, however, it proves significantly faster to progressively double a copy of the original string (concatenating it with itself). Intermediate stages of doubling are appended to an accumulator wherever required for binary composition of the target number.

See the technique of 'Egyptian Multiplication' described in the Rhind Mathematical Papyrus at the British Museum.

Translation of: JavaScript
replicate(5000, "ha")

-- Repetition by 'Egyptian multiplication' -
-- progressively doubling a list, appending
-- stages of doubling to an accumulator where needed for
-- binary assembly of a target length.

-- replicate :: Int -> String -> String
on replicate(n, s)
set out to ""
if n < 1 then return out
set dbl to s

repeat while (n > 1)
if (n mod 2) > 0 then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate

## Applesoft BASIC

FOR I = 1 TO 5 : S\$ = S\$ + "HA" : NEXT

? "X" SPC(20) "X"

Output:

X                    X

## Arturo

print repeat "ha" 5
Output:
hahahahaha

## AutoHotkey

MsgBox % Repeat("ha",5)

Repeat(String,Times)
{
Loop, %Times%
Output .= String
Return Output
}

## AutoIt

#include <String.au3>

ConsoleWrite(_StringRepeat("ha", 5) & @CRLF)

## AWK

function repeat( str, n,    rep, i )
{
for( ; i<n; i++ )
rep = rep str
return rep
}

BEGIN {
print repeat( "ha", 5 )
}

## Babel

main: { "ha" 5 print_repeat }

print_repeat!: { <- { dup << } -> times }

Outputs:

hahahahaha

The '<<' operator prints, 'dup' duplicates the top-of-stack, 'times' does something x number of times. The arrows mean down (<-) and up (->) respectively - it would require a lengthy description to explain what this means, refer to the doc/babel_ref.txt file in the github repo linked from Babel

## BaCon

To repeat a string:

DOTIMES 5
s\$ = s\$ & "ha"
DONE
PRINT s\$
Output:
hahahahaha

To repeat one single character:

PRINT FILL\$(5, ASC("x"))
Output:
xxxxx

## BASIC

### BASIC256

function StringRepeat\$ (s\$, n)
cad\$ = ""
for i = 1 to n
cad\$ += s\$
next i
return cad\$
end function

print StringRepeat\$("rosetta", 1)
print StringRepeat\$("ha", 5)
print StringRepeat\$("*", 5)
end

### QBasic

FUNCTION StringRepeat\$ (s\$, n)
cad\$ = ""
FOR i = 1 TO n
cad\$ = cad\$ + s\$
NEXT i
StringRepeat\$ = cad\$
END FUNCTION

PRINT StringRepeat\$("rosetta", 1)
PRINT StringRepeat\$("ha", 5)
PRINT StringRepeat\$("*", 5)
END

### True BASIC

FUNCTION StringRepeat\$ (s\$, n)
LET cad\$ = ""
FOR i = 1 TO n
LET cad\$ = cad\$ & s\$
NEXT i
LET StringRepeat\$ = cad\$
END FUNCTION

PRINT StringRepeat\$("rosetta", 1)
PRINT StringRepeat\$("ha", 5)
PRINT StringRepeat\$("*", 5)
END

### Yabasic

sub StringRepeat\$ (s\$, n)
cad\$ = ""
for i = 1 to n
cad\$ = cad\$ + s\$
next i
return cad\$
end sub

print StringRepeat\$("rosetta", 1)
print StringRepeat\$("ha", 5)
print StringRepeat\$("*", 5)
end

## Batch File

Commandline implementation

@echo off
if "%2" equ "" goto fail
setlocal enabledelayedexpansion
set char=%1
set num=%2
for /l %%i in (1,1,%num%) do set res=!res!%char%
echo %res%
:fail

'Function' version

@echo off
set /p a=Enter string to repeat :
set /p b=Enter how many times to repeat :
set "c=1"
set "d=%b%"
:a
echo %a%
set "c=%c%+=1"
if /i _"%c%"==_"%d%" (exit /b)
goto :a

'Function' version 2

@echo off
@FOR /L %%i in (0,1,9) DO @CALL :REPEAT %%i
@echo That's it!
@FOR /L %%i in (0,1,9) DO @CALL :REPEAT %%i
@echo.
@echo And that!
@GOTO END

:REPEAT
@echo|set /p="*"
@GOTO:EOF

:END

## BBC BASIC

PRINT STRING\$(5, "ha")

## beeswax

p    <
p0~1<}~< d@<
_VT@1~>yg~9PKd@M'd;

Example:

julia> beeswax("repeat a string.bswx")
sha
i5
hahahahaha
Program finished!

s tells the user that the program expects a string as input. i tells the user that the program expects an integer as input.

## Beef

String s = new String('X', 5);
s.Replace("X", "ha");

And for single character repeats

String s1 = scope .();
s1.PadLeft(5, '*');

## Befunge

v>                ">:#,_v
>29*+00p>~:"0"-    #v_v \$
v      ^p0p00:-1g00< \$            >
v    p00&p0-1g00+4*65< >00g1-:00p#^_@

Input sample:

ha05

Input string has to be zero terminated and less than 18 characters.

Output sample:

hahahahaha

## BQN

(reshape) can all by itself be used to repeat a string to a particular length. This function is just a wrapper around it to repeat n times.

Repeat ← ×⟜≠ ⥊ ⊢

•Show 5 Repeat "Hello"
"HelloHelloHelloHelloHello"

## Bracmat

The code almost explains itself. The repetions are accumulated in a list rep. The str concatenates all elements into a single string, ignoring the white spaces separating the elements.

(repeat=
string N rep
.   !arg:(?string.?N)
& !string:?rep
&   whl
' (!N+-1:>0:?N&!string !rep:?rep)
& str\$!rep
);
repeat\$(ha.5)
hahahahaha

## Brainf***

Prints "ha" 10 times. Note that this method only works for a number of repetitions that fit into the cell size.

+++++ +++++	init first as 10 counter
[-> +++++ +++++<] we add 10 to second each loopround

Now we want to loop 5 times to follow std
+++++
[-> ++++ . ----- -- . +++<] print h and a each loop

and a newline because I'm kind and it looks good
+++++ +++++ +++ . --- .

## Brat

p "ha" * 5  #Prints "hahahahaha"

blsq ) 'h5?*
"hhhhh"
blsq ) "ha"5.*\[
"hahahahaha"

## C

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

char * string_repeat( int n, const char * s ) {
size_t slen = strlen(s);
char * dest = malloc(n*slen+1);

int i; char * p;
for ( i=0, p = dest; i < n; ++i, p += slen ) {
memcpy(p, s, slen);
}
*p = '\0';
return dest;
}

int main() {
char * result = string_repeat(5, "ha");
puts(result);
free(result);
return 0;
}

A variation.

...
char *string_repeat(const char *str, int n)
{
char *pa, *pb;
size_t slen = strlen(str);
char *dest = malloc(n*slen+1);

pa = dest + (n-1)*slen;
strcpy(pa, str);
pb = --pa + slen;
while (pa>=dest) *pa-- = *pb--;
return dest;
}

To repeat a single character

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

char * char_repeat( int n, char c ) {
char * dest = malloc(n+1);
memset(dest, c, n);
dest[n] = '\0';
return dest;
}

int main() {
char * result = char_repeat(5, '*');
puts(result);
free(result);
return 0;
}

If you use GLib, simply use g_strnfill ( gsize length, gchar fill_char ) function.

## C#

string s = "".PadLeft(5, 'X').Replace("X", "ha");

or (with .NET 2+)

string s = new String('X', 5).Replace("X", "ha");

or (with .NET 2+)

string s = String.Join("ha", new string[5 + 1]);

or (with .NET 4+)

string s = String.Concat(Enumerable.Repeat("ha", 5));

To repeat a single character:

string s = "".PadLeft(5, '*');

or (with .NET 2+)

string s = new String('*', 5);

## C++

#include <string>
#include <iostream>

std::string repeat( const std::string &word, int times ) {
std::string result ;
result.reserve(times*word.length()); // avoid repeated reallocation
for ( int a = 0 ; a < times ; a++ )
result += word ;
return result ;
}

int main( ) {
std::cout << repeat( "Ha" , 5 ) << std::endl ;
return 0 ;
}

To repeat a single character:

#include <string>
#include <iostream>

int main( ) {
std::cout << std::string( 5, '*' ) << std::endl ;
return 0 ;
}

### recursive version

#include <string>
#include <iostream>

std::string repeat( const std::string &word, uint times ) {
return
times == 0 ? "" :
times == 1 ? word :
times == 2 ? word + word :
repeat(repeat(word, times / 2), 2) +
repeat(word, times % 2);
}

int main( ) {
std::cout << repeat( "Ha" , 5 ) << std::endl ;
return 0 ;
}

## Ceylon

shared void repeatAString() {
print("ha".repeat(5));
}

## Clipper

Also works with Harbour Project compiler Harbour 3.0.0 (Rev. 16951)

Replicate( "Ha", 5 )

## Clojure

(apply str (repeat 5 "ha"))

## COBOL

Virtually a one-liner.

IDENTIFICATION DIVISION.
PROGRAM-ID. REPEAT-PROGRAM.
DATA DIVISION.
WORKING-STORAGE SECTION.
77  HAHA         PIC A(10).
PROCEDURE DIVISION.
MOVE ALL 'ha' TO HAHA.
DISPLAY HAHA.
STOP RUN.
Output:
hahahahaha

## ColdFusion

<cfset word = 'ha'>
<Cfset n = 5>
<Cfoutput>
<Cfloop from="1" to="#n#" index="i">#word#</Cfloop>
</Cfoutput>

## Common Lisp

(defun repeat-string (n string)
(with-output-to-string (stream)
(loop repeat n do (write-string string stream))))

A version which allocates the result string in one step:

(defun repeat-string (n string
&aux
(len (length string))
(result (make-string (* n len)
:element-type (array-element-type string))))
(loop repeat n
for i from 0 by len
do (setf (subseq result i (+ i len)) string))
result)

For those who love one-liners, even at the expense of readability:

(defun repeat-string (n string)
(format nil "~V@{~a~:*~}" n string))

(princ (repeat-string 5 "hi"))

A single character may be repeated using just the builtin make-string:

(make-string 5 :initial-element #\X)

produces “XXXXX”.

puts "ha" * 5
hahahahaha

## D

Repeating a string:

import std.stdio, std.array;

void main() {
writeln("ha".replicate(5));
}

Repeating a character with vector operations:

import std.stdio;

void main() {
char[] chars;     // create the dynamic array
chars.length = 5; // set the length
chars[] = '*';    // set all characters in the string to '*'
writeln(chars);
}

## DCL

Not exactly what the task asks for but at least it is something;

\$ write sys\$output f\$fao( "!AS!-!AS!-!AS!-!AS!-!AS", "ha" )
\$ write sys\$output f\$fao( "!12*d" )
Output:
\$ @repeat_a_string_and_then_character
hahahahaha
dddddddddddd

## Delphi

Repeat a string

function RepeatString(const s: string; count: cardinal): string;
var
i: Integer;
begin
for i := 1 to count do
Result := Result + s;
end;

Writeln(RepeatString('ha',5));

Repeat a character

Writeln( StringOfChar('a',5) );

Using recursion

function RepeatStr(const s: string; i: Cardinal): string;
begin
if i = 0 then
result := ''
else
result := s + RepeatStr(s, i-1)
end;

Built in RTL function:

StrUtils.DupeString

## DWScript

Repeat a string

PrintLn( StringOfString('abc',5) );

Repeat a character

PrintLn( StringOfChar('a',5) );

## Dyalect

String.Repeat("ha", 5)

## Déjà Vu

!. concat( rep 5 "ha" )
Output:
"hahahahaha"

"ha" * 5

## ECL

After version 4.2.2

IMPORT STD; //Imports the Standard Library

STRING MyBaseString := 'abc';
RepeatedString := STD.Str.Repeat(MyBaseString,3);
RepeatedString;  //returns 'abcabcabc'

Before version 4.2.2

RepeatString(STRING InStr, INTEGER Cnt) := FUNCTION
rec := {STRING Str};
ds  := DATASET(Cnt,TRANSFORM(rec,SELF.Str := InStr));
res := ITERATE(ds,TRANSFORM(rec,SELF.Str := LEFT.Str + RIGHT.Str));
RETURN Res[Cnt].Str;
END;

RepeatString('ha',3);
RepeatString('Who',2);

## Egison

(S.concat (take 5 (repeat1 "ha")))

## Eiffel

repeat_string(a_string: STRING; times: INTEGER): STRING
require
times_positive: times > 0
do
Result := a_string.multiply(times)
end

## Elena

ELENA 4.x :

import system'routines;
import extensions;
import extensions'text;

public program()
{
var s := new Range(0, 5).selectBy:(x => "ha").summarize(new StringWriter())
}

## Elixir

String.duplicate("ha", 5)

## Emacs Lisp

Going via a list to repeat the desired string:

(apply 'concat (make-list 5 "ha"))

A single character can be repeated with make-string:

(make-string 5 ?x)

The cl-loop macro can repeat and concatenate:

Library: cl-lib
(require 'cl-lib)
(cl-loop repeat 5 concat "ha")

## Erlang

repeat(X,N) ->
lists:flatten(lists:duplicate(N,X)).

This will duplicate a string or character N times to produce a new string.

## ERRE

PROCEDURE REPEAT_STRING(S\$,N%->REP\$)
LOCAL I%
REP\$=""
FOR I%=1 TO N% DO
REP\$=REP\$+S\$
END FOR
END PROCEDURE

Note: If N% is less than 1, the result is the empty string "".If S\$ is a one-character string you can use the predefined function STRING\$ as REP\$=STRING\$(S\$,N%).

## Euphoria

A simple loop will do:

sequence s = ""
for i = 1 to 5 do s &= "ha" end for
puts(1,s)

hahahahaha

For repeating a single character:

sequence s = repeat('*',5)

*****

For repeating a string or sequence of numbers:

include std/console.e -- for display
include std/sequence.e -- for repeat_pattern
sequence s = repeat_pattern("ha",5)
sequence n = repeat_pattern({1,2,3},5)
display(s)
display(n)

hahahahaha
{1,2,3,1,2,3,1,2,3,1,2,3,1,2,3}

But wait, here's another way:

include std/console.e -- for display
include std/sequence.e -- for flatten
sequence s = flatten(repeat("ha",5))
display(s)

note: repeat creates a sequence of ha's as shown below; flatten concatenates them.

{
"ha",
"ha",
"ha",
"ha",
"ha"
}

## Explore

The Scratch solution, which requires making variables named "String", "Count", and "Repeated" first, works, unmodified:
https://i.ibb.co/yX3ybt7/Repeat-a-string-in-Explore-using-the-Scratch-solution.png

This example uses a special block located in the Strings category, and also outputs the results of the repeating of the string to a "say" block:
https://i.ibb.co/71x9rwn/Repeat-a-string-in-Explore-using-a-special-block.png

## F#

> String.replicate 5 "ha";;
val it : string = "hahahahaha"

Or

> String.Concat( Array.create 5 "ha" );;
val it : string = "hahahahaha"

## Factor

: repeat-string ( str n -- str' ) swap <repetition> concat ;

"ha" 5 repeat-string print

## Forth

: place-n { src len dest n -- }
0 dest c!
n 0 ?do src len dest +place loop ;

s" ha" pad 5 place-n
pad count type    \ hahahahaha

The same code without the use of locals:

: place-n ( src len dest n -- )
swap >r 0 r@ c!
begin dup while -rot 2dup r@ +place rot 1- repeat
r> 2drop 2drop ;

s" ha" pad 5 place-n
pad count type    \ hahahahaha

Filling a string with a single character is supported by ANS-Forth:

pad 10 char * fill   \ repeat a single character
pad 10 type    \ **********

## Fortran

Works with: Fortran version 90 and later
program test_repeat

write (*, '(a)') repeat ('ha', 5)

end program test_repeat

Output:

hahahahaha

## Free Pascal

strUtils.dupeString('ha', 5)

Repetition of a single character:

stringOfChar('*', 5)

If the repeated character happens to be the space character:

space(5)

## FreeBASIC

' FB 1.05.0 Win64

' A character is essentially a string of length 1 in FB though there is a built-in function, String,
' which creates a string by repeating a character a given number of times.

' To avoid repeated concatenation (a slow operation) when the string to be repeated has a length
' greater than one, we instead create a buffer of the required size and then fill that.

Function repeat(s As String, n As Integer) As String
If n < 1 Then Return ""
If n = 1 Then Return s
Var size = Len(s)
If size = 0 Then Return s  ' empty string
If size = 1 Then Return String(n, s[0])  ' repeated single character
Var buffer = Space(size * n)  'create buffer for size > 1
For i As Integer = 0 To n - 1
For j As Integer = 0 To size - 1
buffer[i * size + j] = s[j]
Next j
Next i
Return buffer
End Function

Print repeat("rosetta", 1)
Print repeat("ha", 5)
Print repeat("*", 5)
Print
Print "Press any key to quit program"
Sleep
Output:
rosetta
hahahahaha
*****

## Frink

println[repeat["ha", 5]]

## FutureBasic

include "NSLog.incl"

CFStringRef repeatStr
repeatStr = @"Hello, World!\n"
NSLog( @"%@", fn StringByPaddingToLength( @"", 50 * len(repeatStr), repeatStr, 0 ) )

HandleEvents
Output:
[50 line repetitions of "Hello, World!"]

## Gambas

Public Sub Main()

Print String\$(5, "ha")

End

Output = hahahahaha

## GAP

Concatenation(ListWithIdenticalEntries(10, "BOB "));
"BOB BOB BOB BOB BOB BOB BOB BOB BOB BOB "

## Glee

'*' %% 5
'ha' => Str;
Str# => Len;
1..Len %% (Len * 5) => Idx;
Str [Idx] \$;
'ha'=>S[1..(S#)%%(S# *5)]

## Go

fmt.Println(strings.Repeat("ha", 5))        // ==> "hahahahaha"

There is no special way to repeat a single character, other than to convert the character to a string. The following works:

fmt.Println(strings.Repeat(string('h'), 5)) // prints hhhhh

## Groovy

println 'ha' * 5

## Harbour

? Replicate( "Ha", 5 )

## Haskell

For a string of finite length:

concat \$ replicate 5 "ha"

Or with list-monad (a bit obscure):

[1..5] >> "ha"

Or with Control.Applicative:

[1..5] *> "ha"

For an infinitely long string:

cycle "ha"

To repeat a single character:

replicate 5 '*'

Or, unpacking the mechanism of replicate a little, and using a mappend-based rep in lieu of the cons-based repeat, so that we can skip a subsequent concat:

repString :: String -> Int -> String
repString s n =
let rep x = xs
where
xs = mappend x xs
in take (n * length s) (rep s)

main :: IO ()
main = print \$ repString "ha" 5
Output:
"hahahahaha"

As the number of repetitions grows, however, it may become more efficient to repeat by progressive duplication (mappend to self), mappending to an accumulator only where required for binary composition of the target length. (i.e. Rhind Papyrus 'Egyptian' or 'Ethiopian' multiplication):

import Data.Tuple (swap)
import Data.List (unfoldr)
import Control.Monad (join)

-- BY RHIND PAPYRUS 'EGYPTIAN' OR 'ETHIOPIAN' MULTIPLICATION ------------------
repString :: Int -> String -> String
repString n s =
foldr
(\(d, x) a ->
if d > 0 -- Is this power of 2 needed for the binary recomposition ?
then mappend a x
else a)
mempty \$
zip
(unfoldr
(\h ->
if h > 0
then Just \$ swap (quotRem h 2) -- Binary decomposition of n
else Nothing)
n)
(iterate (join mappend) s) -- Iterative duplication ( mappend to self )

-- TEST -----------------------------------------------------------------------
main :: IO ()
main = print \$ repString 500 "ha"

## HicEst

CHARACTER out*20

EDIT(Text=out, Insert="ha", DO=5)

## Icon and Unicon

The procedure repl is a supplied function in Icon and Unicon.

procedure main(args)
write(repl(integer(!args) | 5))
end

If it weren't, one way to write it is:

procedure repl(s, n)
every (ns := "") ||:= |s\(0 <= n)
return ns
end

## Idris

strRepeat : Nat -> String -> String
strRepeat Z s = ""
strRepeat (S n) s = s ++ strRepeat n s

chrRepeat : Nat -> Char -> String
chrRepeat Z c = ""
chrRepeat (S n) c = strCons c \$ chrRepeat n c

## Inform 7

Home is a room.

To decide which indexed text is (T - indexed text) repeated (N - number) times:
let temp be indexed text;
repeat with M running from 1 to N:
let temp be "[temp][T]";
decide on temp.

When play begins:
say "ha" repeated 5 times;
end the story.

## IS-BASIC

10 PRINT STRING\$("ha",5)
100 DEF STRING\$(S\$,N)
105   LET ST\$=""
110   FOR I=1 TO N
120     LET ST\$=ST\$&S\$
130   NEXT
140   LET STRING\$=ST\$
150 END DEF

## J

5 # '*'               NB. repeat each item 5 times
*****
5 # 'ha'              NB. repeat each item 5 times
hhhhhaaaaa
5 ((* #) \$ ]) 'ha'    NB. repeat array 5 times
hahahahaha
5 ;@# < 'ha'          NB. using boxing to treat the array as a whole
hahahahaha

## Java

Works with: Java version 1.5+

There's no method or operator to do this in Java, so you have to do it yourself.

public static String repeat(String str, int times) {
StringBuilder sb = new StringBuilder(str.length() * times);
for (int i = 0; i < times; i++)
sb.append(str);
return sb.toString();
}

public static void main(String[] args) {
System.out.println(repeat("ha", 5));
}

Or even shorter:

public static String repeat(String str, int times) {
return new String(new char[times]).replace("\0", str);
}

In Apache Commons Lang, there is a StringUtils.repeat() method.

## JavaScript

#### Extending the String prototype

This solution creates an empty array of length n+1, then uses the array's join method to effectively concatenate the string n times. Note that extending the prototype of built-in objects is not a good idea if the code is to run in a shared workspace.

String.prototype.repeat = function(n) {
return new Array(1 + (n || 0)).join(this);
}

console.log("ha".repeat(5));  // hahahahaha

As of ES6, `repeat` is built in, so this can be written as:

console.log("ha".repeat(5));  // hahahahaha

#### Repetition by Egyptian multiplication

For larger numbers of repetitions, however, it proves significantly faster to progressively double a copy of the original string (concatenating it with itself). Intermediate stages of doubling are appended to an accumulator wherever required for binary composition of the target number.

See the technique of 'Egyptian Multiplication' described in the Rhind Mathematical Papyrus at the British Museum.

(() => {
'use strict';

// replicate :: Int -> String -> String
const replicate = (n, s) => {
let v = [s],
o = [];
if (n < 1) return o;
while (n > 1) {
if (n & 1) o = o + v;
n >>= 1;
v = v + v;
}
return o.concat(v);
};

return replicate(5000, "ha")
})();

#### Concat . replicate

Or, more generically, we could derive repeat as the composition of concat and replicate

(() => {
'use strict';

// repeat :: Int -> String -> String
const repeat = (n, s) =>
concat(replicate(n, s));

// GENERIC FUNCTIONS ------------------------------------------------------

// concat :: [[a]] -> [a] | [String] -> String
const concat = xs =>
xs.length > 0 ? (() => {
const unit = typeof xs[0] === 'string' ? '' : [];
return unit.concat.apply(unit, xs);
})() : [];

// replicate :: Int -> a -> [a]
const replicate = (n, x) =>
Array.from({
length: n
}, () => x);

// TEST -------------------------------------------------------------------
return repeat(5, 'ha');
})();
Output:
hahahahaha

## jq

"a " * 3' # => "a a a "

Note that if the integer multiplicand is 0, then the result is the JSON value null.

## Julia

Works with: Julia version 1.0
@show "ha" ^ 5

# The ^ operator is really just call to the `repeat` function
@show repeat("ha", 5)

,/5#,"ha"
"hahahahaha"

5#"*"
"*****"

## Kotlin

fun main(args: Array<String>) {
println("ha".repeat(5))
}

Or more fancy:

operator fun String.times(n: Int) = this.repeat(n)

fun main(args: Array<String>) = println("ha" * 5)

## LabVIEW

I don't know if there is a built-in function for this, but it is easily achieved with a For loop and Concatenate Strings.

## Lambdatalk

{S.map {lambda {_} ha} {S.serie 1 10}}
-> ha ha ha ha ha ha ha ha ha ha

or

{S.replace \s
by
in {S.map {lambda {_} ha}
{S.serie 1 10}}}
-> hahahahahahahahahaha

or

{def repeat
{lambda {:w :n}
{if {< :n 0}
then
else :w{repeat :w {- :n 1}}}}}
-> repeat

{repeat ha 10}
-> hahahahahahahahahahaha

## langur

This example looks like Perl, but the x operator doesn't just multiply strings in langur.

"ha" x 5

## Lasso

'ha'*5 // hahahahaha
loop(5) => {^ 'ha' ^} // hahahahaha

## LFE

(string:copies '"ha" 5)

## Liberty BASIC

a\$ ="ha "
print StringRepeat\$( a\$, 5)

end

function StringRepeat\$( in\$, n)
o\$ =""
for i =1 to n
o\$ =o\$ +in\$
next i
StringRepeat\$ =o\$
end function

## Lingo

• Take a string and repeat it some number of times.
on rep (str, n)
res = ""
repeat with i = 1 to n
put str after res
end repeat
return res
end
put rep("ha", 5)
-- "hahahahaha"
• If there is a simpler/more efficient way to repeat a single “character”...
put bytearray(5, chartonum("*")).readRawString(5)
-- "*****"

## LiveCode

on mouseUp
put repeatString("ha", 5)
end mouseUp

function repeatString str n
repeat n times
put str after t
end repeat
return t
end repeatString

## Logo

to copies :n :thing [:acc "||]
if :n = 0 [output :acc]
output (copies :n-1 :thing combine :acc :thing)
end

or using cascade:

show cascade 5 [combine "ha ?] "||    ; hahahahaha

Lhogho doesn't have cascade (yet), nor does it have the initialise a missing parameter capability demonstrated by the [:acc "||] above.

to copies :n :thing :acc
if :n = 0 [output :acc]
output (copies :n-1 :thing combine :acc :thing)
end

print copies 5 "ha "||

## Lua

function repeats(s, n) return n > 0 and s .. repeats(s, n-1) or "" end

Or use native string library function

string.rep(s,n)

## Maple

There are many ways to do this in Maple. First, the "right" (most efficient) way is to use the supplied procedures for this purpose.

> use StringTools in
>       Repeat( "abc", 10 ); # repeat an arbitrary string
>       Fill( "x", 20 )      # repeat a character
> end use;
"abcabcabcabcabcabcabcabcabcabc"

"xxxxxxxxxxxxxxxxxxxx"

These next two are essentially the same, but are less efficient (though still linear) because they create a sequence of 10 strings before concatenating them (with the built-in procedure cat) to form the result.

> cat( "abc" \$ 10 );
"abcabcabcabcabcabcabcabcabcabc"

> cat( seq( "abc", i = 1 .. 10 ) );
"abcabcabcabcabcabcabcabcabcabc"

You can build up a string in a loop, but this is highly inefficient (quadratic); don't do this.

> s := "":
> to 10 do s := cat( s, "abc" ) end: s;
"abcabcabcabcabcabcabcabcabcabc"

If you need to build up a string incrementally, use a StringBuffer object, which keeps things linear.

Finally, note that strings and characters are not distinct datatypes in Maple; a character is just a string of length one.

## Mathematica/Wolfram Language

(* solution 1 *)
rep[n_Integer,s_String]:=Apply[StringJoin,ConstantArray[s,{n}]]
(* solution 2 -- @@ is the infix form of Apply[] *)
rep[n_Integer,s_String]:=StringJoin@@Table[s,{n}]
(* solution 3 -- demonstrating another of the large number of looping constructs available *)
rep[n_Integer,s_String]:=Nest[StringJoin[s, #] &,s,n-1]

## MATLAB / Octave

function S = repeat(s , n)
S = repmat(s , [1,n]) ;
return

Note 1: The repetition is returned, not displayed.
Note 2: To repeat a string, use single quotes. Example: S=repeat('ha',5)

## Maxima

"\$*"(s, n) := apply(sconcat, makelist(s, n))\$
infix("\$*")\$

"abc" \$* 5;
/* "abcabcabcabcabc" */

## Mercury

Mercury's 'string' module provides an efficient char-repeater. The following uses string.builder to repeat strings.

:- module repeat.
:- interface.
:- import_module string, char, int.

:- func repeat_char(char, int) = string.
:- func repeat(string, int) = string.

:- implementation.
:- import_module stream, stream.string_writer, string.builder.

repeat_char(C, N) = string.duplicate_char(C, N).

repeat(String, Count) = Repeated :-
S0 = string.builder.init,
Repeated = string.builder.to_string(S),
printn(string.builder.handle, Count, String, S0, S).

:- pred printn(Stream, int, string, State, State)
<= (stream.writer(Stream, string, State),
stream.writer(Stream, character, State)).
:- mode printn(in, in, in, di, uo) is det.
printn(Stream, N, String, !S) :-
( N > 0 ->
print(Stream, String, !S),
printn(Stream, N - 1, String, !S)
; true ).

## min

Works with: min version 0.19.3
"ha" 5 repeat print
Output:
hahahahaha

str = "Lol"
print str * 5
Output:
LolLolLolLolLol

## Mirah

x = StringBuilder.new

5.times do
x.append "ha"
end

puts x # ==> "hahahahaha"

## Monte

var s := "ha " * 5
traceln(s)

## MontiLang

|ha| 5 * PRINT .

Or with a loop

FOR 5
|ha| OUT .
ENDFOR || PRINT .

Or ...

|ha| FOR 5 OUT ENDFOR . || PRINT .

## MUMPS

RPTSTR(S,N)
;Repeat a string S for N times
NEW I
FOR I=1:1:N WRITE S
KILL I
QUIT
RPTSTR1(S,N) ;Functionally equivalent, but denser to read
F I=1:1:N W S
Q

This last example uses the \$PIECE function.

;Even better (more terse)
S x="",\$P(x,"-",10)="-"
W x

## Nanoquery

In Nanoquery, multiplying strings by an integer returns a new string with the original value repeated.

"ha" * 5

## Neko

/* Repeat a string, in Neko */
var srep = function(s, n) {
var str = ""
while n > 0 {
str += s
n -= 1
}
return str
}

\$print(srep("ha", 5), "\n")
Output:
prompt\$ nekoc srep.neko
prompt\$ neko srep
hahahahaha

## Nemerle

Any of the methods shown in the C# solution would also work for Nemerle, but they're all semantically awkward. This example uses an extension method to wrap one of the awkward techniques in order to clarify the semantics (which is also possible in C#, there's nothing really Nemerle specific here except the syntax).

using System;
using System.Console;

module StrRep
{
Repeat(this s : string, n : int) : string
{
String('x', n).Replace("x", s)
}

Main() : void
{
WriteLine("ha".Repeat(5));
WriteLine("*".Repeat(5));
WriteLine(String('*', 5)); // repeating single char

}
}

## NetRexx

NetRexx has built in functions to manipulate strings. The most appropriate for this task is the copies() function:

/* NetRexx */

ha5 = 'ha'.copies(5)

There are several other built-in functions that can be used to achieve the same result depending on need:

/* NetRexx */
sampleStr = 'ha' -- string to duplicate
say '   COPIES:' sampleStr.copies(5)
say 'CHANGESTR:' '.....'.changestr('.', sampleStr)

sampleChr = '*' -- character to duplicate
say '     LEFT:' sampleChr.left(5, sampleChr)
say '    RIGHT:' sampleChr.right(5, sampleChr)
say '   CENTRE:' sampleChr.centre(5, sampleChr)
say '  OVERLAY:' sampleChr.overlay(sampleChr, 1, 5, sampleChr)
say '   SUBSTR:' ''.substr(1, 5, sampleChr)
say 'TRANSLATE:' '.....'.translate(sampleChr, '.')

(dup "ha" 5)

## Nim

import strutils

# Repeat a char.
echo repeat('a', 5)     # -> "aaaaa".

# Repeat a string.
echo repeat("ha", 5)    # -> "hahahahaha".

## Objeck

bundle Default {
class Repeat {
function : Main(args : String[]) ~ Nil {
Repeat("ha", 5)->PrintLine();
}

function : Repeat(string : String, max : Int) ~ String {
repeat : String := String->New();
for(i := 0; i < max; i += 1;) {
repeat->Append(string);
};

return repeat;
}
}
}

## Objective-C

Objective-C allows developers to extend existing an existing class by adding additional methods to the class without needing to subclass. These extensions are called categories. Category methods are available to all instances of the class, as well as any instances of its subclasses.

This task provides us with an opportunity to visit this aspect of the language feature.

We will extend NSString, the de facto Objective-C string class in environments that are either compatible with or descend directly from the OPENSTEP specification, such as GNUstep and Mac OS X, respectively, with a method that accomplishes the described task.

@interface NSString (RosettaCodeAddition)
- (NSString *) repeatStringByNumberOfTimes: (NSUInteger) times;
@end

@implementation NSString (RosettaCodeAddition)
- (NSString *) repeatStringByNumberOfTimes: (NSUInteger) times {
return [@"" stringByPaddingToLength:[self length]*times withString:self startingAtIndex:0];
}
@end

Now, let's put it to use:

// Instantiate an NSString by sending an NSString literal our new
// -repeatByNumberOfTimes: selector.
NSString *aString = [@"ha" repeatStringByNumberOfTimes:5];

// Display the NSString.
NSLog(@"%@", aString);

## OCaml

Since Ocaml 4.02 strings are immutable, as is convenient for a functional language. Mutable strings are now implemented in the module Bytes.

let string_repeat s n =
let s = Bytes.of_string s in
let len = Bytes.length s in
let res = Bytes.create (n * len) in
for i = 0 to pred n do
Bytes.blit s 0 res (i * len) len
done;
(Bytes.to_string res)
;;
which gives the signature
val string_repeat : string -> int -> string = <fun>

testing in the toplevel:

# string_repeat "Hiuoa" 3 ;;
- : string = "HiuoaHiuoaHiuoa"

Alternately create an array initialized to s, and concat:

let string_repeat s n =
String.concat "" (Array.to_list (Array.make n s))
;;

Or:

let string_repeat s n =
Array.fold_left (^) "" (Array.make n s)
;;

To repeat a single character use:

String.make 5 '*'

## Oforth

StringBuffer new "abcd" <<n(5)

## OpenEdge/Progress

MESSAGE FILL( "ha", 5 ) VIEW-AS ALERT-BOX.

## OxygenBasic

'REPEATING A CHARACTER

print string 10,"A" 'result AAAAAAAAAA

'REPEATING A STRING

function RepeatString(string s,sys n) as string
sys i, le=len s
if le=0 then exit function
n*=le
function=nuls n
'
for i=1 to n step le
mid function,i,s
next
end function

print RepeatString "ABC",3 'result ABCABCABC

## Oz

We have to write a function for this:

declare
fun {Repeat Xs N}
if N > 0 then
{Append Xs {Repeat Xs N-1}}
else
nil
end
end
in
{System.showInfo {Repeat "Ha" 5}}

## PARI/GP

### Version #1. Based on recursion.

This solution is recursive and unimaginably bad. Slightly less bad versions can be designed, but that's not the point: don't use GP for text processing if you can avoid it. If you really need to, it's easy to create an efficient function in PARI (see C) and pass that to GP.

repeat(s,n)={
if(n, Str(repeat(s, n-1), s), "")
};

concat() joins together a vector of strings, in this case a single string repeated.

repeat(s,n)=concat(vector(n,i, s));

This solution is recursive and slightly less bad than the others for large n.

repeat(s,n)={
if(n<4, return(concat(vector(n,i, s))));
if(n%2,
Str(repeat(Str(s,s),n\2),s)
,
repeat(Str(s,s),n\2)
);
}

### Version #2. Simple loop based.

Works with: PARI/GP version 2.7.4 and above

Basic set of string functions is very handy for presentation purposes. At the same time, it is true that PARI/GP is not an appropriate tool for the heavy text processing.

\\ Repeat a string str the specified number of times ntimes and return composed string.
\\ 3/3/2016 aev
srepeat(str,ntimes)={
my(srez=str,nt=ntimes-1);
if(ntimes<1||#str==0,return(""));
if(ntimes==1,return(str));
for(i=1,nt, srez=concat(srez,str));
return(srez);
}

{
\\ TESTS
print(" *** Testing srepeat:");
print("1.",srepeat("a",5));
print("2.",srepeat("ab",5));
print("3.",srepeat("c",1));
print("4.|",srepeat("d",0),"|");
print("5.|",srepeat("",5),"|");
print1("6."); for(i=1,10000000, srepeat("e",10));
}
Output:
*** Testing srepeat:
1.aaaaa
2.ababababab
3.c
4.||
5.||
6.
(16:00) gp > ##
***   last result computed in 1min, 2,939 ms.

## Pascal

See Delphi or Free Pascal, as standard Pascal does not know strings of unlimited length.

"ha" x 5

## Phix

?repeat('*',5)
?join(repeat("ha",5),"")
Output:
"*****"
"hahahahaha"

## Phixmonti

def rep  /# s n -- s #/
"" swap
for drop
over chain
endfor
nip
enddef

"ha" 5 rep print

Same result (simple character):

65 5 rep
65 5 repeat
'A' 5 repeat

## PHP

str_repeat("ha", 5)

## PicoLisp

(pack (need 5 "ha"))
-> "hahahahaha"

or:

(pack (make (do 5 (link "ha"))))
-> "hahahahaha"

"ha"*5;

## PL/I

/* To repeat a string a variable number of times: */

s = repeat('ha', 4);

/* or */

s = copy('ha', 5);

/* To repeat a single character a fixed number of times: */

s = (5)'h';     /* asigns 'hhhhh' to s. */

## Plain English

To run:
Start up.
Put "ha" into a string.
Append the string to itself given 5.
Write the string on the console.
Fill another string with the asterisk byte given 5.
Write the other string on the console.
Wait for the escape key.
Shut down.

To append a string to itself given a number:
If the number is less than 1, exit.
Privatize the string.
Privatize the number.
Subtract 1 from the number.
Append the string to the original string given the number.
Output:
hahahahaha
*****

"ha" 5 *

## PostScript

% the comments show the stack content after the line was executed
% where rcount is the repeat count, "o" is for orignal,
% "f" is for final, and iter is the for loop variable
%
% usage: rcount ostring times -> fstring

/times {
dup length dup    % rcount ostring olength olength
4 3 roll          % ostring olength olength rcount
mul dup string    % ostring olength flength fstring
4 1 roll          % fstring ostring olength flength
1 sub 0 3 1 roll  % fstring ostring 0 olength flength_minus_one
{                 % fstring ostring iter
1 index 3 index % fstring ostring iter ostring fstring
3 1 roll        % fstring ostring fstring iter ostring
putinterval     % fstring ostring
} for
pop               % fstring
} def

## PowerBASIC

MSGBOX REPEAT\$(5, "ha")

## PowerShell

"ha" * 5  # ==> "hahahahaha"

## Processing

void setup() {
String rep = repeat("ha", 5);
println(rep);
}
String repeat(String str, int times) {
// make an array of n chars,
// replace each char with str,
// and return as a new String
return new String(new char[times]).replace("\0", str);
}

### Processing Python mode

def setup():
rep = repeat("ha", 5)
println(rep)

def repeat(s, times):
return s * times

## Prolog

%repeat(Str,Num,Res).
repeat(Str,1,Str).
repeat(Str,Num,Res):-
Num1 is Num-1,
repeat(Str,Num1,Res1),
string_concat(Str, Res1, Res).

### alternative using DCG strings

This tail-recursive DCG implemention is more efficient than anything using lists:append .

Works with: SWI-Prolog version 7
:- system:set_prolog_flag(double_quotes,chars) .

repeat(SOURCEz0,COUNT0,TARGETz)
:-
prolog:phrase(repeat(SOURCEz0,COUNT0),TARGETz)
.

%! repeat(SOURCEz0,COUNT0)//2

repeat(_SOURCEz0_,0)
-->
! ,
[]
.

repeat(SOURCEz0,COUNT0)
-->
SOURCEz0 ,
{ COUNT is COUNT0 - 1 } ,
repeat(SOURCEz0,COUNT)
.
Output:
/*
?- repeat("ha",5,TARGETz) .
TARGETz = [h, a, h, a, h, a, h, a, h, a].

?-
*/
:- begin_tests(basic) .

:- system:set_prolog_flag(double_quotes,chars) .

test('1',[])
:-
repeat("a",2,"aa")
.

test('2',[])
:-
repeat("ha",2,"haha")
.

test('3',[])
:-
repeat("ha",3,"hahaha")
.

test('4',[])
:-
repeat("",3,"")
.

test('5',[])
:-
repeat("ha",0,"")
.

test('6',[])
:-
repeat("ha",1,"ha")
.

:- end_tests(basic) .

## Pure

str_repeat is defined by pattern-matching: repeating any string 0 times results in the empty string; while repeating it more than 0 times results in the concatenation of the string and (n-1) further repeats.

> str_repeat 0 s = "";
> str_repeat n s = s + (str_repeat (n-1) s) if n>0;
> str_repeat 5 "ha";
"hahahahaha"
>

You can define str_repeat using infinite lazy list (stream).

str_repeat n::int s::string = string \$ take n \$ cycle (s:[]);

## PureBasic

Procedure.s RepeatString(count, text\$=" ")
Protected i, ret\$=""

For i = 1 To count
ret\$ + text\$
Next
ProcedureReturn ret\$
EndProcedure

Debug RepeatString(5, "ha")

## Python

"ha" * 5  # ==> "hahahahaha"

"Characters" are just strings of length one.

the other way also works:

5 * "ha"  # ==> "hahahahaha"

### Using a Function

def repeat(s, times):
return s * times

print(repeat("ha", 5))
Output:
hahahahaha

### Using Lambda

x = lambda a: a * 5
print(x("ha"))
Output:
hahahahaha

## Quackery

\$ "ha" 5 of echo\$

Output:

hahahahaha

strrep("ha", 5)

## Racket

#lang racket
;; fast
(define (string-repeat n str)
(string-append* (make-list n str)))
(string-repeat 5 "ha") ; => "hahahahaha"

To repeat a single character:

(make-string 5 #\*) => "*****"

## Raku

(formerly Perl 6)

print "ha" x 5

(Note that the x operator isn't quite the same as in Perl 5: it now only creates strings. To create lists, use xx.)

## RapidQ

'For a single char
showmessage String\$(10, "-")

'For strings with more than one char
function Repeat\$(Expr as string, Count as integer) as string
dim x as integer
for x = 1 to Count
Result = Result + Expr
next
end function

showmessage Repeat\$("ha", 5)

## REALbasic

Function Repeat(s As String, count As Integer) As String
Dim output As String
For i As Integer = 0 To count
output = output + s
Next
Return output
End Function

## REBOL

head insert/dup "" "ha" 5

## Red

>> str: "Add duplicates to string"
>> insert/dup str "ha" 3
== "hahahaAdd duplicates to string"
>> insert/dup tail str "ha" 3
== "hahahaAdd duplicates to stringhahaha"

## ReScript

Js.log(Js.String2.repeat("ha", 5))

## Retro

with strings'
: repeatString ( \$n-\$ )
1- [ dup ] dip [ over prepend ] times nip ;

"ha" 5 repeatString

## REXX

Since the REXX language only supports the "character" type, it's not surprising that there are so many ways to skin a cat.

/*REXX program to show various ways to repeat a string (or repeat a single char).*/

/*all examples are equivalent, but not created equal.*/

/*───────────────────────────────────────────*/
y='ha'
z=copies(y,5)
/*───────────────────────────────────────────*/
z=copies( 'ha', 5 )
/*───────────────────────────────────────────*/
y='ha'
z=y||y||y||y||y
/*───────────────────────────────────────────*/
y='ha'
z=y || y || y || y || y    /*same as previous, but the "big sky" version*/
/*───────────────────────────────────────────*/
y='ha'
z=''
do 5
z=z||y
end
/*───────────────────────────────────────────*/
y="ha"
z=
do 5
z=z||y
end
/*───────────────────────────────────────────*/
y="ha"
z=
do i=101 to 105
z=z||y
end

/*───────────────────────────────────────────*/
y='+'
z=left('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=right('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=substr('',1,5,y)
/*───────────────────────────────────────────*/
y='+'
z=center('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=centre('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=space('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=translate('@@@@@',y,"@")
/*───────────────────────────────────────────*/
y='abcdef'
z=five(y)
exit

five: procedure expose y; parse arg g
if length(g)>=5*length(y) then return g
return five(y||g)
/*───────────────────────────────────────────*/
y='something wicked this way comes.'
z=y||y||y||y||y||y||y||y||y||y||y||y|\y||y||y
z=left(z,5*length(y))
/*───────────────────────────────────────────*/
y='+'
z=copies('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=lower('',1,5,y)
/*───────────────────────────────────────────*/
y='+'
z=lower('',,5,y)
/*───────────────────────────────────────────*/
z='+'
z=upper('',1,5,y)
/*───────────────────────────────────────────*/
z=upper('',,5,y)
/*───────────────────────────────────────────*/

y='charter bus.'
z='*****'
z=changestr('*',z,y)
/*───────────────────────────────────────────*/
y='what the hey!'
z=
do until length(z)==5*length(y)
z=z||y
end
/*───────────────────────────────────────────*/
y='what the hey!'
z=
do until length(z)==5*length(y)
z=insert(z,0,y)
end
/*───────────────────────────────────────────*/
y='yippie ki yay'
z=
do i=1 by 5 for 5
z=overlay(y,z,i)
end
/*───────────────────────────────────────────*/
y='+'
z=justify('',5,y)
/*───────────────────────────────────────────*/
whatever_this_variable_is_____it_aint_referenced_directly= 'boy oh boy.'
z=; signal me; me:
do 5
z=z||strip(subword(sourceline(sigl-1),2),,"'")
end
/*───────────────────────────────────────────*/
y="any more examples & the angry townfolk with pitchforks will burn the castle."
parse value y||y||y||y||y with z

exit                                   /*stick a fork in it, we're done.*/

Some older REXXes don't have a changestr bif, so one is included here ──► CHANGESTR.REX.

## Ring

Copy("ha" , 5)  # ==> "hahahahaha"

## Ruby

"ha" * 5  # ==> "hahahahaha"

a\$ = "ha "
for i = 1 to 5
a1\$ = a1\$ + a\$
next i
a\$ = a1\$
print a\$

## Rust

std::iter::repeat("ha").take(5).collect::<String>(); // ==> "hahahahaha"

Since 1.16:

"ha".repeat(5); // ==> "hahahahaha"

## Scala

"ha" * 5 // ==> "hahahahaha"

## Scheme

(define (string-repeat n str)
(apply string-append (vector->list (make-vector n str))))

with SRFI 1:

(define (string-repeat n str)
(fold string-append "" (make-list n str)))
(string-repeat 5 "ha") ==> "hahahahaha"

To repeat a single character:

(make-string 5 #\*)

## Scratch

This example requires making variables named "String", "Count", and "Repeated" first.

## sed

Number of ampersands indicates number of repetitions.

\$ echo ha | sed 's/.*/&&&&&/'
hahahahaha

## Seed7

\$ include "seed7_05.s7i";

const proc: main is func
begin
writeln("ha" mult 5);
end func;

Output:

hahahahaha

## SenseTalk

put "Ho!" repeated 3 times

put "Merry" repeated to length 12

Output:

Ho!Ho!Ho!
MerryMerryMe

## Sidef

'ha' * 5;  # ==> 'hahahahaha'

## Sinclair ZX81 BASIC

Works with 1k of RAM. This program defines a subroutine that expects to find a string and a number of times to repeat it; but all it then does is loop and concatenate, so making it a separate subroutine is arguably overkill.

10 LET S\$="HA"
20 LET N=5
30 GOSUB 60
40 PRINT T\$
50 STOP
60 LET T\$=""
70 FOR I=1 TO N
80 LET T\$=T\$+S\$
90 NEXT I
100 RETURN

## Smalltalk

If n is a small constant, then simply concatenating n times will do; for example, n=5::

v := 'ha'.
v,v,v,v,v
Works with: Pharo version 1.4
Works with: Smalltalk/X

By creating a collection of n 'ha', and joining them to a string:

((1 to: n) collect: [:x | 'ha']) joinUsing: ''.
or:
Works with: Smalltalk/X
(Array new:n withAll:'ha') asStringWith:''.

By creating a WriteStream, and putting N times the string 'ha' into it:

ws := '' writeStream.
n timesRepeat: [ws nextPutAll: 'ha'].
ws contents.

alternatively:

(String streamContents:[:ws | n timesRepeat: [ws nextPutAll: 'ha']])

all evaluate to:

hahahahaha

A string containing a repeated character is generated with:

String new:n withAll:\$*
Works with: VA Smalltalk
(String new:n) atAllPut:\$*

## SNOBOL4

output = dupl("ha",5)
end

## Sparkling

spn:3> repeat("na", 8) .. " Batman!"
= nananananananana Batman!

## SQL

select rpad('', 10, 'ha')

## SQL PL

Works with: Db2 LUW
VALUES REPEAT('ha', 5);
VALUES RPAD('', 10, 'ha');

Output:

db2 -t
db2 => VALUES REPEAT('ha', 5);

1
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
hahahahaha

1 record(s) selected.

db2 => VALUES RPAD('', 10, 'ha');

1
----------
hahahahaha

1 record(s) selected.

## Standard ML

fun string_repeat (s, n) =
concat (List.tabulate (n, fn _ => s))
;

testing in the interpreter:

- string_repeat ("Hiuoa", 3) ;
val it = "HiuoaHiuoaHiuoa" : string

To repeat a single character:

fun char_repeat (c, n) =
implode (List.tabulate (n, fn _ => c))
;

. scalar a="ha"
. scalar b=a*5
. display b
hahahahaha

## Suneido

'ha'.Repeat(5)  -->  "hahahahaha"
'*'.Repeat(5)  -->  "*****"

## Swift

### The Builtin Way

print(String(repeating:"*", count: 5))
Output:
*****

### Functions

func * (left:String, right:Int) -> String {
return String(repeating:left, count:right)
}

print ("HA" * 5)
Output:

HAHAHAHAHA

### Extensions

Using extensions to do the repetition which makes for an easier syntax when repeating Strings, and using String.extend() to get faster evaluation.

extension String {
// Slower version
func repeatString(n: Int) -> String {
return Array(count: n, repeatedValue: self).joinWithSeparator("")
}

// Faster version
// benchmarked with a 1000 characters and 100 repeats the fast version is approx 500 000 times faster :-)
func repeatString2(n:Int) -> String {
var result = self
for _ in 1 ..< n {
result.appendContentsOf(self)   // Note that String.appendContentsOf is up to 10 times faster than "result += self"
}
return result
}
}

print( "ha".repeatString(5) )
print( "he".repeatString2(5) )
Output:
hahahahaha
hehehehehe

To repeat a single character:

String(count:5, repeatedValue:"*" as Character)

Note that using the String version on a string of 1 Character, or the repeat single Character version is timewise close to the same. No point in using the Character version for efficiency (tested with repeating up to 100 000 times).

### Bitwise Iterative Version

The following version is an enhanced version of the recursive ActionScript, where we're using bit operation along with iterative doubling of the string to get to the correctly repeated version of the text in the most effective manner without recursion. When benchmarked against the plain iterative version in previous section, this version is marginally better, but only my a very small percentage. The critical factor for making the repeat function effective when using larger strings (1000 characters) and multiple repeats (1000 repeats :-) ) was to to exchange the '+=' with 'String.extend' method.

extension String {
func repeatBiterative(count: Int) -> String {
var reduceCount = count
var result = ""
var doubled = self
while reduceCount != 0 {
if reduceCount & 1 == 1 {
result.appendContentsOf(doubled)
}
reduceCount >>= 1
if reduceCount != 0 {
doubled.appendContentsOf(doubled)
}
}
return result
}
}

"He".repeatBiterative(5)
Output:
"HeHeHeHeHe"

## Tailspin

'\$:1..5 -> 'ha';' -> !OUT::write
Output:
hahahahaha

## Tcl

string repeat "ha" 5  ;# => hahahahaha

## TorqueScript

--Eepos

function strRep(%str,%int)
{
for(%i = 0; %i < %int; %i++)
{
%rstr = %rstr@%str;
}

return %rstr;
}

## Tosh

when flag clicked
set String to "meow"
set Count to 4
set Repeated to ""
repeat Count
set Repeated to (join (Repeated) (String))
end
stop this script

## Transact-SQL

select REPLICATE( 'ha', 5 )

## TUSCRIPT

\$\$ MODE TUSCRIPT
repeatstring=REPEAT ("ha",5)

## UNIX Shell

### Using printf

Works with: bash
Works with: ksh93
Works with: zsh
printf "ha"%.0s {1..5}

With ksh93 and zsh, the count can vary.

Works with: ksh93
Works with: zsh
i=5
printf "ha"%.0s {1..\$i}

With bash, {1..\$i} fails, because brace expansion happens before variable substitution. The fix uses eval.

Works with: bash
Works with: ksh93
Works with: zsh
i=5
eval "printf 'ha'%.0s {1..\$i}"

For the general case, one must escape any % or \ characters in the string, because printf would interpret those characters.

Works with: bash
Works with: ksh93
Works with: zsh
reprint() {
typeset e="\$(sed -e 's,%,%%,g' -e 's,\\,\\\\,g' <<<"\$1")"
eval 'printf "\$e"%.0s '"{1..\$2}"
}
reprint '%  ha  \' 5

### Using repeat

Works with: zsh
Works with: csh
len=12; str='='
repeat \$len printf "\$str"

### Using head -c

head -c is a GNU extension, so it only works with those systems. (Also, this script can only repeat a single character.)

Works with: Bourne Shell
width=72; char='='
head -c \${width} < /dev/zero | tr '\0' "\$char"

## Ursala

#import nat

repeat = ^|DlSL/~& iota

#cast %s

example = repeat('ha',5)

output:

'hahahahaha'

## Vala

Repeat a string 5 times:

string s = "ha";
string copy = "";
for (int x = 0; x < 5; x++)
copy += s;

Fill a string with a char N times:

string s = string.nfill(5, 'c');

## VBA

Repeat a string

Public Function RepeatStr(aString As String, aNumber As Integer) As String
Dim bString As String, i As Integer
bString = ""
For i = 1 To aNumber
bString = bString & aString
Next i
RepeatStr = bString
End Function

Debug.Print RepeatStr("ha", 5)
Output:
hahahahaha

Note: "String(5, "ha") in VBA produces "hhhhh" (only the first character is repeated)!

An alternative method:

Public Function RepeatString(stText As String, iQty As Integer) As String
RepeatString = Replace(String(iQty, "x"), "x", stText)
End Function

Repeat a character

Debug.Print String(5, "x")
Output:
xxxxx

## VBScript

Works with: Windows Script Host version *
' VBScript has a String() function that can repeat a character a given number of times
' but this only works with single characters (or the 1st char of a string):
WScript.Echo String(10, "123")	' Displays "1111111111"

' To repeat a string of chars, you can use either of the following "hacks"...
WScript.Echo Replace(Space(10), " ", "Ha")
WScript.Echo Replace(String(10, "X"), "X", "Ha")

## Vedit macro language

Ins_Text("ha", COUNT, 5)

## Visual Basic

Works with: Visual Basic version VB6 Standard

Repeat a string

Public Function StrRepeat(s As String, n As Integer) As String
Dim r As String, i As Integer
r = ""
For i = 1 To n
r = r & s
Next i
StrRepeat = r
End Function

Debug.Print StrRepeat("ha", 5)
Output:
hahahahaha

An alternative method:

Public Function StrRepeat(sText As String, n As Integer) As String
StrRepeat = Replace(String(n, "*"), "*", sText)
End Function

Repeat a character

Debug.Print String(5, "x")
Output:
xxxxx

## Visual Basic .NET

Repeat a string

Debug.Print(Replace(Space(5), " ", "Ha"))
Output:
HaHaHaHaHa

Repeat a character

Debug.Print(StrDup(5, "x"))
Debug.Print("".PadRight(5, "x"))
Debug.Print("".PadLeft(5, "x"))
Output:
xxxxx
xxxxx
xxxxx

## Visual FoxPro

Use the built in function REPLICATE(string, number):

? REPLICATE("HO", 3)

produces

HOHOHO

## Vlang

// Repeat a string, in V
// Tectonics: v run repeat-a-string.v
module main
import strings

// starts here
pub fn main() {
// A strings module function to repeat strings
println(strings.repeat_string("ha", 5))

// Another strings module function to repeat a byte
// This indexes the string to get the first byte of the rune array
println(strings.repeat("*"[0], 5))
}
Output:
prompt\$ v run rosetta/repeat-a-string.v
hahahahaha
*****

## Wart

def (s * n) :case (string? s)
with outstring
repeat n
pr s

("ha" * 5)
=> "hahahahaha"

## Wortel

@join "" @rep 5 "ha" ; returns "hahahahaha"

As a function:

^(\@join "" @rep)

## Wren

System.print("ha" * 5)
Output:
hahahahaha

## XPL0

cod T=12; int I; for I gets 1,5 do T(0,"ha")
Output:
hahahahaha

## Yorick

array("ha", 5)(sum)

## Z80 Assembly

PrintChar equ &BB5A ;Amstrad CPC BIOS call, prints the ascii code in the accumulator to the screen.

org &8000
ld b,5                 ; repeat 5 times

loop:
call PrintImmediate
byte "ha",0
djnz loop

ret                    ; return to basic
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
PrintImmediate:
pop hl                 ; get the return address into HL, it's the start of the embedded string.
call PrintString
; inc hl               ; if your strings are null-terminated you can omit this, since a 0 equals the "NOP" instruction
jp (hl)                ; acts as a ret, returning execution to the instruction just after the embedded string.

PrintString:
ld a,(hl)              ; read in a character from the string
or a                   ; if your strings are null-terminated you can use this as a shortcut, otherwise use the compare instruction
ret z                  ; exit once the terminator is reached.
call PrintChar         ; BIOS call, all regs are preserved.
inc hl                 ; next char
jr PrintString         ; back to start.
Output:
hahahahaha

## zig

At compile-time:

const laugh = "ha" ** 5;

Note that to achieve this at run-time in zig (in order to avoid hidden overflows) you must manage the memory yourself.

const std = @import("std");
const warn = std.debug.warn;

const Allocator = std.mem.Allocator;

fn repeat(s: []const u8, times: u16, allocator: *Allocator) ![]u8 {
const repeated = try allocator.alloc(u8, s.len*times);

var i: usize = 0;
while (i < s.len*times) : (i += 1) {
repeated[i] = s[i % 2];
}

return repeated;
}

pub fn main() !void {
const allocator = std.debug.global_allocator;
const ex = try repeat("ha", 5, allocator);
defer allocator.free(ex);
}

## zkl

Same as Ruby

"ha" * 5  # --> "hahahahaha"