View source for String append

{{task|Basic language learning}}
[[Category:String manipulation]]
[[Category: String manipulation]]
{{basic data operation}} 
[[Category:Simple]]

Most languages provide a way to concatenate two string values, but some languages also provide a convenient way to append in-place to an existing string variable without referring to the variable twice.


;Task:
Create a string variable equal to any text value. 

Append the string variable with another string literal in the most idiomatic way, without double reference if your language supports it. 

Show the contents of the variable after the append operation.
<br><br>
=={{header|11l}}==
{{trans|Python}}

<syntaxhighlight lang="11l">V s = ‘12345678’
s ‘’= ‘9!’
print(s)</syntaxhighlight>

{{out}}
<pre>
123456789!
</pre>

=={{header|AArch64 Assembly}}==
{{works with|as|Raspberry Pi 3B version Buster 64 bits}}
<syntaxhighlight lang="aarch64 assembly">
/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program appendstr64.s   */

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
 
.equ BUFFERSIZE,          100
/*******************************************/
/* Initialized data                        */
/*******************************************/
.data
szMessString:            .asciz "String :\n"
szString1:              .asciz "Alphabet : "
sComplement:            .fill BUFFERSIZE,1,0
szString2:              .asciz "abcdefghijklmnopqrstuvwxyz"
 
szCarriageReturn:       .asciz "\n"
/*******************************************/
/* UnInitialized data                      */
/*******************************************/
.bss 
/*******************************************/
/*  code section                           */
/*******************************************/
.text
.global main 
main: 
 
    ldr x0,qAdrszMessString               // display message
    bl affichageMess
    ldr x0,qAdrszString1                  // display begin string
    bl affichageMess
    ldr x0,qAdrszCarriageReturn           // display return line
    bl affichageMess
    ldr x0,qAdrszString1
    ldr x1,qAdrszString2
    bl append                             // append sting2 to string1
    ldr x0,qAdrszMessString
    bl affichageMess
    ldr x0,qAdrszString1                  // display string
    bl affichageMess 
    ldr x0,qAdrszCarriageReturn
    bl affichageMess
 
100:                                      // standard end of the program
    mov x0,0                              // return code
    mov x8,EXIT                           // request to exit program
    svc 0                                 // perform system call
qAdrszMessString:         .quad szMessString
qAdrszString1:            .quad szString1
qAdrszString2:            .quad szString2
qAdrszCarriageReturn:     .quad szCarriageReturn
/**************************************************/
/*     append two strings                         */ 
/**************************************************/
/* x0 contains the address of the string1 */
/* x1 contains the address of the string2 */
append:
    stp x1,lr,[sp,-16]!            // save  registers
    mov x2,#0                      // counter byte string 1
1:
    ldrb w3,[x0,x2]                // load byte string 1
    cmp x3,#0                      // zero final ?
    add x4,x2,1
    csel x2,x4,x2,ne               // if x3 not equal 0, x2 = X2 +1 else x2
    bne 1b                         // no -> loop
    mov x4,#0                      // counter byte string 2
2:
    ldrb w3,[x1,x4]                // load byte string 2
    strb w3,[x0,x2]                // store byte string 1
    cbz x3,100f                    // zero final ?
    add x2,x2,1                    // no -> increment counter 1
    add x4,x4,1                    // no -> increment counter 2
    b 2b                           // no -> loop
100:

    ldp x1,lr,[sp],16              // restaur  2 registers
    ret                            // return to address lr x30
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
</syntaxhighlight>
{{Output}}
<pre>
String :
Alphabet :
String :
Alphabet : abcdefghijklmnopqrstuvwxyz
</pre>

=={{header|Action!}}==
<syntaxhighlight lang="action!">
CHAR ARRAY S1,S2

Proc Main()
 S1="Hello, "
 S2="world!";
 Sassign(S1,S2,S1(0)+1)
 Print(S1)
Return
</syntaxhighlight>
{{out}}
<pre>
Hello, world!
</pre>


=={{header|Ada}}==
<syntaxhighlight lang="ada">
with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
with Ada.Text_IO.Unbounded_Io; use Ada.Text_IO.Unbounded_IO;

procedure String_Append is
   Str : Unbounded_String := To_Unbounded_String("Hello");
begin
   Append(Str, ", world!");
   Put_Line(Str);
end String_Append;
</syntaxhighlight>
{{out}}
<pre>
Hello, world!
</pre>

=={{header|ALGOL 68}}==
{{works with|ALGOL 68|Revision 1.}}
{{works with|ALGOL 68G|Any - tested with release [http://sourceforge.net/projects/algol68/files/algol68g/algol68g-2.7 algol68g-2.7].}}
{{works with|ELLA ALGOL 68|Any (with appropriate job cards).}}
'''File: String_append.a68'''<syntaxhighlight lang="algol68">#!/usr/bin/a68g --script #
# -*- coding: utf-8 -*- #

STRING str := "12345678";
str +:= "9!";
print(str)</syntaxhighlight>
{{out}}
<pre>
123456789!
</pre>

=={{header|Amazing Hopper}}==
<syntaxhighlight lang="c">
#include <jambo.h>

Main
    r="un corderito", s="María tenía", t="felpudo"
    
    Multicat ( s," ",r," ",t ),Get utf8, and print it
    
    d=0
    Let ' d := Utf8( Cat( Cat ( s, " un " ), t ) )'
    Printnl ( "\n",d )
End
</syntaxhighlight>
{{out}}
<pre>
María tenía un corderito felpudo
María tenía un felpudo
</pre>

=={{header|ARM Assembly}}==
{{works with|as|Raspberry Pi}}
<syntaxhighlight lang="arm assembly">
/* ARM assembly Raspberry PI  */
/*  program appendstr.s   */

/* Constantes    */
.equ STDOUT, 1                           @ Linux output console
.equ EXIT,   1                           @ Linux syscall
.equ WRITE,  4                           @ Linux syscall

.equ BUFFERSIZE,          100

/* Initialized data */
.data
szMessString:            .asciz "String :\n"
szString1:              .asciz "Alphabet : "
sComplement:            .fill BUFFERSIZE,1,0
szString2:              .asciz "abcdefghijklmnopqrstuvwxyz"

szCarriageReturn:       .asciz "\n"

/* UnInitialized data */
.bss 

/*  code section */
.text
.global main 
main: 

    ldr r0,iAdrszMessString                     @ display message
    bl affichageMess
    ldr r0,iAdrszString1                        @ display begin string
    bl affichageMess
    ldr r0,iAdrszCarriageReturn                 @ display line return
    bl affichageMess
    ldr r0,iAdrszString1
    ldr r1,iAdrszString2
    bl append                                   @ append sting2 to string1
    ldr r0,iAdrszMessString
    bl affichageMess
    ldr r0,iAdrszString1                        @ display string
    bl affichageMess 
    ldr r0,iAdrszCarriageReturn
    bl affichageMess

100:                                            @ standard end of the program
    mov r0, #0                                  @ return code
    mov r7, #EXIT                               @ request to exit program
    svc 0                                       @ perform system call
iAdrszMessString:         .int szMessString
iAdrszString1:            .int szString1
iAdrszString2:            .int szString2
iAdrszCarriageReturn:     .int szCarriageReturn
/******************************************************************/
/*     append two strings                         */ 
/******************************************************************/
/* r0 contains the address of the string1 */
/* r1 contains the address of the string2 */
append:
    push {r0,r1,r2,r7,lr}                       @ save  registers 
    mov r2,#0                                   @ counter byte string 1
1:
    ldrb r3,[r0,r2]                             @ load byte string 1
    cmp r3,#0                                   @ zero final ?
    addne r2,#1
    bne 1b                                      @ no -> loop
    mov r4,#0                                   @ counter byte string 2
2:
    ldrb r3,[r1,r4]                             @ load byte string 2
    strb r3,[r0,r2]                             @ store byte string 1
    cmp r3,#0                                   @ zero final ?
    addne r2,#1                                 @ no -> increment counter 1
    addne r4,#1                                 @ no -> increment counter 2
    bne 2b                                      @ no -> loop
100:
    pop {r0,r1,r2,r7,lr}                        @ restaur registers
    bx lr                                       @ return

/******************************************************************/
/*     display text with size calculation                         */ 
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
    push {r0,r1,r2,r7,lr}                       @ save  registers 
    mov r2,#0                                   @ counter length */
1:                                              @ loop length calculation
    ldrb r1,[r0,r2]                             @ read octet start position + index 
    cmp r1,#0                                   @ if 0 its over
    addne r2,r2,#1                              @ else add 1 in the length
    bne 1b                                      @ and loop 
                                                @ so here r2 contains the length of the message 
    mov r1,r0                                   @ address message in r1 
    mov r0,#STDOUT                              @ code to write to the standard output Linux
    mov r7, #WRITE                              @ code call system "write" 
    svc #0                                      @ call system
    pop {r0,r1,r2,r7,lr}                        @ restaur registers
    bx lr                                       @ return


</syntaxhighlight>

=={{header|AppleScript}}==
<syntaxhighlight lang="applescript">
set {a, b} to {"Apple", "Script"}
set a to a & b
return a as string
</syntaxhighlight>

{{out}}
<pre>
"AppleScript"
</pre>

=={{header|APL}}==
<syntaxhighlight lang="apl">      s←'hello'
      s,'world'
helloworld</syntaxhighlight>

=={{header|Arturo}}==
<syntaxhighlight lang="rebol">print join ["Hello" "World"]

a: new "Hello"
'a ++ "World"
print a

b: new "Hello"
append 'b "World"
print b

c: "Hello"
print append c "World"</syntaxhighlight>

{{out}}

<pre>HelloWorld
HelloWorld
HelloWorld
HelloWorld</pre>

=={{header|Asymptote}}==
<syntaxhighlight lang="asymptote">string s = "Hello";
s = s + " Wo";
s += "rld!";
write(s);</syntaxhighlight>

=={{header|AutoHotkey}}==
<syntaxhighlight lang="autohotkey">s := "Hello, "
s .= "world."
MsgBox % s</syntaxhighlight>
{{out}}<pre>Hello, world.</pre>

=={{header|Avail}}==
Avail's normal strings are immutable, however string ''variables'' can leverage tuple's appending-assignment method, <code>_↑++=_</code>.

<syntaxhighlight lang="avail">str : string := "99 bottles of ";
str ++= "beer";
Print: str;</syntaxhighlight>

Note that one can define methods similar to this, thanks to the ''variable occurrence'' message pattern, <code>_↑</code>, whose slot accepts a variable usage and then passes the variable container itself as the corresponding argument. Consider the source for the append used above:

<syntaxhighlight lang="avail">Public method "_↑++=_" is
[
	var : read tuple/write ⊥,
	t : tuple
|
	var ?= eject var ++ t;
] : ⊤;</syntaxhighlight>
(<code>eject</code> and <code>?=</code> are methods used for unassign-retrieving and assigning to a variable, respectively, only needed when dealing with the containers themselves.)

=={{header|AWK}}==
<syntaxhighlight lang="awk">
# syntax: GAWK -f STRING_APPEND.AWK
BEGIN {
    s = "foo"
    s = s "bar"
    print(s)
    exit(0)
}
</syntaxhighlight>
{{out}}
<pre>
foobar
</pre>

=={{header|Axe}}==
<syntaxhighlight lang="axe">Lbl STRCAT
Copy(r₂,r₁+length(r₁),length(r₂)+1)
r₁
Return</syntaxhighlight>

=={{header|BASIC}}==
==={{header|Applesoft BASIC}}===
<syntaxhighlight lang="basic">S$ = "Hello"
S$ = S$ + " World!"
PRINT S$</syntaxhighlight>

==={{header|BaCon}}===
<syntaxhighlight lang="freebasic">
A$ = "Hello"
A$ = A$ & " World!"
PRINT A$
</syntaxhighlight>  

==={{header|BASIC256}}===
<syntaxhighlight lang="freebasic">a$ = "He"
a$ = a$ & "llo"
a$ = a$ + " Wo"
a$ += "rld"
a$ &= "!"
print a$</syntaxhighlight>

==={{header|BBC BASIC}}===
<syntaxhighlight lang="bbc basic">      S$="Hello"
      S$+=" World!"
      PRINT S$
      END</syntaxhighlight>
{{out}}
<pre>Hello World!</pre>

==={{header|Commodore BASIC}}===
<syntaxhighlight lang="gwbasic">10 S$ = "HELLO"
20 S$ = S$ + " WORLD!"
30 PRINT S$
40 END</syntaxhighlight>
{{out}}
<pre>HELLO WORLD!</pre>

==={{header|Chipmunk Basic}}===
{{works with|Chipmunk Basic|3.6.4}}
<syntaxhighlight lang="qbasic">10 a$ = "Hello"
20 a$ = a$ + " World!"
30 print a$</syntaxhighlight>

==={{header|GW-BASIC}}===
{{works with|PC-BASIC|any}}
{{works with|BASICA}}
{{works with|Applesoft Basic}}
{{works with|Chipmunk Basic}}
{{works with|QBasic}}
{{works with|Quite BASIC}}
{{works with|MSX BASIC}}
<syntaxhighlight lang="qbasic">10 LET a$ = "Hello"
20 LET a$ = a$ + " World!"
30 PRINT a$</syntaxhighlight>

==={{header|IS-BASIC}}===
<syntaxhighlight lang="is-basic">100 LET S$="Hello"
110 LET S$=S$&" World!"
120 PRINT S$</syntaxhighlight>

==={{header|Liberty BASIC}}===
<syntaxhighlight lang="lb">a$ = "Hello"
a$ = a$ + " World"
a$ = a$ ; "!"
print a$</syntaxhighlight>

==={{header|MSX Basic}}===
The [[#GW-BASIC|GW-BASIC]] solution works without any changes.

==={{header|QBasic}}===
{{works with|Liberty BASIC}}
{{works with|QB64}}
{{works with|Run BASIC}}
{{works with|Yabasic}}
<syntaxhighlight lang="qbasic">a$ = "Hello"
a$ = a$ + " World!"
PRINT a$</syntaxhighlight>

==={{header|Quite BASIC}}===
The [[#GW-BASIC|GW-BASIC]] solution works without any changes.

==={{header|Run BASIC}}===
{{works with|Liberty BASIC}}
{{works with|QB64}}
{{works with|QBasic}}
{{works with|Yabasic}}
<syntaxhighlight lang="runbasic">a$ = "Hello"
a$ = a$ + " World!"
print a$</syntaxhighlight>

==={{header|True BASIC}}===
<syntaxhighlight lang="qbasic">LET a$ = "Hello"
LET a$ = a$ & " World!"
PRINT a$
END</syntaxhighlight>

==={{header|uBasic/4tH}}===
<syntaxhighlight lang="qbasic">a := "Hello"
a = Join (a, " World!")
Print Show(a)</syntaxhighlight>

==={{header|XBasic}}===
{{works with|Windows XBasic}}
<syntaxhighlight lang="qbasic">PROGRAM	"String append"
VERSION	"0.0000"

DECLARE FUNCTION  Entry ()

FUNCTION  Entry ()
  a$ = "Hello"
  a$ = a$ + " World!"
  PRINT a$
END FUNCTION
END PROGRAM</syntaxhighlight>

==={{header|Yabasic}}===
{{works with|Liberty BASIC}}
{{works with|QB64}}
{{works with|QBasic}}
{{works with|Run BASIC}}
<syntaxhighlight lang="yabasic">a$ = "Hello"
a$ = a$ + " World!"
print a$</syntaxhighlight>


=={{header|Binary Lambda Calculus}}==
BLC program
<pre>18 16 46 80 05 bc bc fd f6 e0 69 6f 6e</pre>
based on https://github.com/tromp/AIT/blob/master/rosetta/catstrings.lam
appends "ion" to "on" to output "onion".

=={{header|BQN}}==
<syntaxhighlight lang="bqn">str ← "oneTwo"

•Out str ∾↩ "Three"

str</syntaxhighlight>
{{out}}
<pre>oneTwoThree
"oneTwoThree"</pre>

=={{header|Bracmat}}==
<syntaxhighlight lang="bracmat">str="Hello";
str$(!str " World!"):?str;
out$!str;</syntaxhighlight>
{{out}}
<pre>Hello World!</pre>

=={{header|C}}==
<syntaxhighlight lang="c">#include<stdio.h>
#include<string.h>

int main()
{
    char str[24]="Good Morning";
    char *cstr=" to all";
    char *cstr2=" !!!";
    int x=0;
    //failure when space allocated to str is insufficient.

    if(sizeof(str)>strlen(str)+strlen(cstr)+strlen(cstr2))
            {
                /* 1st method*/
                strcat(str,cstr);

                /*2nd method*/
                x=strlen(str);
                sprintf(&str[x],"%s",cstr2);

                printf("%s\n",str);

            }
    return 0;
}</syntaxhighlight>
{{out}}
<pre>Good Morning to all !!!</pre>

=={{header|C sharp|C#}}==
<syntaxhighlight lang="csharp">class Program
{
    static void Main(string[] args)
    {
        string x = "foo";
        x += "bar";
        System.Console.WriteLine(x);
    }
}</syntaxhighlight>

=={{header|C++}}==
<syntaxhighlight lang="cpp">#include <iostream>
#include <string>

int main( ) {
   std::string greeting( "Hello" ) ;
   greeting.append( " , world!" ) ;
   std::cout << greeting << std::endl ;
   return 0 ;
}</syntaxhighlight>
{{out}}
<pre>Hello , world!</pre>

=={{header|Clojure}}==
Using global vars.
<syntaxhighlight lang="clojure">user=> (def s "app")
#'user/s
user=> s
"app"
user=> (def s (str s "end"))
#'user/s
user=> s
"append"</syntaxhighlight>

Using local bindings.
<syntaxhighlight lang="clojure">
user=> (let [s "ap", s (str s "pend")] s)
"append"</syntaxhighlight>

=={{header|COBOL}}==
COBOL is not really a variable length field programming language.  Most data items are fixed in size at compile time.

This example uses OCCURS DEPENDING ON, and ''reference modification'' to simulate a string append, all within an already maximally bounded character field.  This type of programming task, while possible, is not overly common in COBOL applications.

{{works with|GnuCOBOL}}
<syntaxhighlight lang="cobol">      identification division.                                         
       program-id. string-append.                                       

       data division.
       working-storage section.
       01 some-string.
          05 elements pic x occurs 0 to 80 times depending on limiter.
       01 limiter     usage index value 7.
       01 current     usage index.

       procedure division.
       append-main.

       move "Hello, " to some-string

      *> extend the limit and move using reference modification
       set current to length of some-string
       set limiter up by 5
       move "world" to some-string(current + 1:)
       display some-string

       goback.
       end program string-append.
</syntaxhighlight>
{{out}}
<pre>$ cobc -xj string-append.cob
Hello, world</pre>

=={{header|CoffeeScript}}==
{{works with|Node.js}}
<syntaxhighlight lang="coffeescript">a = "Hello, "
b = "World!"
c = a + b

console.log c</syntaxhighlight>
Or with concat:
<syntaxhighlight lang="coffeescript">console.log "Hello, ".concat "World!"</syntaxhighlight>
{{out}}
<pre>Hello, World!</pre>

=={{header|Common Lisp}}==
Similar to the [[String append#Racket| Racket]] solution, a macro is necessary to append in-place:
<syntaxhighlight lang="lisp">(defmacro concatenatef (s &rest strs) 
  "Append additional strings to the first string in-place."
  `(setf ,s (concatenate 'string ,s ,@strs)))
(defvar *str* "foo")
(concatenatef *str* "bar")
(format T "~a~%" *str*)
(concatenatef *str* "baz" "abc" "def")
(format T "~a~%" *str*)</syntaxhighlight>

Output:
<pre>foobar
foobarbazabcdef</pre>

=={{header|D}}==
<syntaxhighlight lang="d">import std.stdio;

void main() {
    string s = "Hello";
    s ~= " world!"; 
    writeln(s);
}</syntaxhighlight>
{{out}}
<pre>Hello world!</pre>

=={{header|Dart}}==
<syntaxhighlight lang="dart">void main() {
  String str = "Hello";
  str = str + " World!";
  print(str);
}</syntaxhighlight>

=={{header|DBL}}==
<syntaxhighlight lang="dbl">;Concatenate "Hello world!"
STR='Hello'
STR(%TRIM(STR)+2:5)='world'
STR(%TRIM(STR)+1:1)='!'</syntaxhighlight>

=={{header|Delphi}}==
{{libheader| System.SysUtils}}
<syntaxhighlight lang="delphi">
program String_append;

{$APPTYPE CONSOLE}

uses
  System.SysUtils;

type
  TStringHelper = record helper for string
    procedure Append(str: string);
  end;

{ TStringHelper }

procedure TStringHelper.Append(str: string);
begin
  Self := self + str;
end;

begin
  var h: string;

  // with + operator
  h := 'Hello';
  h := h + ' World';
  writeln(h);

  // with a function concat
  h := 'Hello';
  h := Concat(h, ' World');
  writeln(h);

  // with helper
  h := 'Hello';
  h.Append(' World');
  writeln(h);
  readln;
end.</syntaxhighlight>
{{out}}
<pre>Hello World
Hello World
Hello World</pre>


=={{header|Dyalect}}==
<syntaxhighlight lang="dyalect">var str = "foo"
str += str
print(str)</syntaxhighlight>

=={{header|EasyLang}}==
<syntaxhighlight lang="text">a$ = "hello"
a$ &= " world"
print a$</syntaxhighlight>

=={{header|EchoLisp}}==
<syntaxhighlight lang="lisp">
;; Solution from Common Lisp and Racket
(define-syntax-rule (set-append! str tail) 
   (set! str (string-append str tail)))

(define name "Albert") → name

(set-append! name " de Jeumont-Schneidre")
name
   → "Albert de Jeumont-Schneidre"
</syntaxhighlight>

=={{header|Elena}}==
ELENA 6.x :
<syntaxhighlight lang="elena">import extensions'text;

public program()
{
    var s := StringWriter.load("Hello");
    s.append(" World");
    
    console.writeLine(s).readChar()
}</syntaxhighlight>

=={{header|Elixir}}==
<syntaxhighlight lang="elixir">iex(60)> s = "Hello"
"Hello"
iex(61)> s <> " World!"
"Hello World!"</syntaxhighlight>

=={{header|Emacs Lisp}}==

While strings in Emacs Lisp are mutable, they're fixed size. Therefore the <code>concat</code> function creates a new string and the existing string must be referenced twice:

<syntaxhighlight lang="lisp">(defvar str "foo")
(setq str (concat str "bar"))
str ;=> "foobar"</syntaxhighlight>

This can be hidden by using a macro such as <code>cl-callf</code> which expands into the above code:

{{libheader|cl-lib}}
<syntaxhighlight lang="lisp">(require 'cl-lib)

(defvar str "foo")
(cl-callf concat str "bar")
str ;=> "foobar"</syntaxhighlight>

Buffers can be thought of as expandable strings:

<syntaxhighlight lang="lisp">(let ((buf (get-buffer-create "*foo*")))
  (with-current-buffer buf
    (insert "foo"))
  (with-current-buffer buf
    (goto-char (point-max))
    (insert "bar")
    (buffer-string)))
;; => "foobar"</syntaxhighlight>

=={{header|EMal}}==
<syntaxhighlight lang="emal">
^|EMal has mutable strings;
 |the append method changes the value in-place.
 |^
text hello = "Hello, "
hello.append("world!")
writeLine(hello)
</syntaxhighlight>
{{out}}
<pre>
Hello, world!
</pre>

=={{header|Erlang}}==
{{out}}
<pre>
1> S = "Hello".
"Hello"
2> S ++ " world".
"Hello world"
</pre>

=={{header|Euphoria}}==
<syntaxhighlight lang="euphoria">
sequence string = "String"

printf(1,"%s\n",{string})

string &= " is now longer\n"

printf(1,"%s",{string})
</syntaxhighlight>
{{out}}
<pre>
String
String is now longer
</pre>

=={{header|F_Sharp|F#}}==
Strings are immutable in .NET. To append (to the same variable) the variable has to be declared mutable.
<syntaxhighlight lang="fsharp">let mutable x = "foo"
x <- x + "bar"
printfn "%s" x</syntaxhighlight>

=={{header|Factor}}==
<syntaxhighlight lang="factor">"Hello, " "world!" append</syntaxhighlight>
{{out}}
<pre>
"Hello, world!"
</pre>

=={{header|Falcon}}==
<syntaxhighlight lang="falcon">
/* Added by Aykayayciti Earl Lamont Montgomery
April 10th, 2018 */

s1, s2 = "Hello", "Foo"
> s1 + " World"
printl(s2 + " bar")
</syntaxhighlight>
{{out}}
<pre>
Hello World
Foo bar
[Finished in 0.2s]
</pre>

=={{header|Forth}}==
<syntaxhighlight lang="forth">\ Strings in Forth are simply named memory locations

create astring  256 allot   \ create a "string"

s" Hello " astring PLACE     \ initialize the string

s" World!" astring +PLACE   \ append with "+place"</syntaxhighlight>

Test at the console

<syntaxhighlight lang="text">  ok
s" Hello " astring place  ok
s" World!" astring +place  ok
astring count type Hello World! ok
</syntaxhighlight>

=={{header|Fortran}}==

'''Using deferred length character strings:'''

<syntaxhighlight lang="fortran">
program main

 character(len=:),allocatable :: str

 str = 'hello'
 str = str//' world'

 write(*,*) str

end program main
</syntaxhighlight>

{{out}}
<pre>hello world</pre>


'''Using pre-allocated character strings:'''

<syntaxhighlight lang="fortran">
program str_append
    implicit none

    character(len=20) :: str

    str= 'String'
    str(len_trim(str)+1:) = 'Append'
    print *, str

end program str_append
</syntaxhighlight>

{{out}}
<pre>StringAppend</pre>

=={{header|FreeBASIC}}==
<syntaxhighlight lang="freebasic">' FB 1.05.0 Win64

Var s = "String"
s += " append"
Print s 
Sleep</syntaxhighlight>

{{out}}
<pre>
String append
</pre>

=={{header|FutureBasic}}==
<syntaxhighlight lang="futurebasic">
Str255 s

s = "Hello"
s += " World!"

print s

HandleEvents
</syntaxhighlight>

=={{header|Gambas}}==
'''[https://gambas-playground.proko.eu/?gist=0b17e205d56985c8cd1ff108c6fc9ca4 Click this link to run this code]'''
<syntaxhighlight lang="gambas">Public Sub Main()
Dim sString As String = "Hello "

sString &= "World!"
Print sString

End</syntaxhighlight>
Output:
<pre>
Hello World!
</pre>

=={{header|GDScript}}==
{{works with|Godot|4.0.1}}

<syntaxhighlight lang="gdscript">
extends MainLoop


func _process(_delta: float) -> bool:
	var string: String = "123"
	string += "abc"
	print(string)
	return true # Exit
</syntaxhighlight>

{{out}}
<pre>
123abc
</pre>

=={{header|Genie}}==
<syntaxhighlight lang="genie">[indent=4]
/* String append, in Genie */
init
    str:string = "Hello"
    str += ", world"

    print str</syntaxhighlight>
{{out}}
<pre>prompt$ valac stringAppend.gs
prompt$ ./stringAppend
Hello, world</pre>

=={{header|GlovePIE}}==
<syntaxhighlight lang="glovepie">var.string="This is "
var.string+="Sparta!"
debug=var.string</syntaxhighlight>

=={{header|Go}}==
<syntaxhighlight lang="go">s := "foo"
s += "bar"</syntaxhighlight>

=== String Builder ===
The first solution redefines the string variable every time. It might be short in code but it uses much CPU cycles. A better way is to use `string.Builder` but it is not a string. It is more like a buffer which can produce a string. And it really appends the string to the existing variable.
<syntaxhighlight lang="go">
package main

import (
  "fmt"
  "strings"
)

func main() {
  var s strings.Builder
  s.WriteString("foo")
  s.WriteString("bar")
  fmt.Print(s.String())
}
</syntaxhighlight>
{{out}}
foobar

=={{header|Gosu}}==
<syntaxhighlight lang="gosu">// Example 1
var s = "a"
s += "b"
s += "c"
print(s)

// Example 2
print("a" + "b" + "c")

// Example 3
var a = "a"
var b = "b"
var c = "c"
print("${a}${b}${c}")</syntaxhighlight>
{{out}}
<pre>
abc
abc
abc
</pre>

=={{header|Groovy}}==
<syntaxhighlight lang="groovy">
class Append{
static void main(String[] args){
def c="Hello ";
def d="world";
def e=c+d;
println(e);
}
}
</syntaxhighlight>
{{out}}
<pre>
Hello world
</pre>

=={{header|Haskell}}==

<syntaxhighlight lang="haskell">
main = putStrLn ("Hello" ++ "World")
</syntaxhighlight>

=={{header|Icon}} and {{header|Unicon}}==
In both languages you can:

<syntaxhighlight lang="unicon">
procedure main()
    s := "foo"
    s ||:= "bar"
    write(s)
end
</syntaxhighlight>

Outputs:

<pre>
->ss
foobar
->
</pre>

=={{header|J}}==
<syntaxhighlight lang="j">   s=: 'new'
   s
new
   s=: s,' value'   NB. append is in-place
   s
new value</syntaxhighlight>

=={{header|Java}}==
There are multiple ways to append string values in Java.<br />
The most common way is through the plus operator.
<syntaxhighlight lang="java">
String string = "abc" + "def";
</syntaxhighlight>
Which can also be written as
<syntaxhighlight lang="java">
String string = "abc";
string += "def";
</syntaxhighlight>
There is also the ''String.concat'' method
<syntaxhighlight lang="java">
String string = "abc".concat("def");
</syntaxhighlight>
You could use a ''StringBuilder'' object if you're appending multiple strings.
<syntaxhighlight lang="java">
StringBuilder string = new StringBuilder();
string.append("abc").append("def");
</syntaxhighlight>
''StringBuilder'' also conveniently lets you insert strings within strings.<br />
So, you can also append a string as follows
<syntaxhighlight lang="java">
StringBuilder string = new StringBuilder();
string.append("abc");
string.insert(3, "def");
</syntaxhighlight>
A less common approach would be to use the ''String.format'' or ''String.formatted'' methods.
<syntaxhighlight lang="java">
String string = String.format("%s%s", "abc", "def");
</syntaxhighlight>
<syntaxhighlight lang="java">
String string = "%s%s".formatted("abc", "def");
</syntaxhighlight>
All of these methods will produce the following string
<pre>
abcdef
</pre>
<br />
Alternately
<syntaxhighlight lang="java">String sa = "Hello";
sa += ", World!";
System.out.println(sa);

StringBuilder ba = new StringBuilder();
ba.append("Hello");
ba.append(", World!");
System.out.println(ba.toString());</syntaxhighlight>
{{out}}
<pre>
Hello, World!
Hello, World!
</pre>

=={{header|JavaScript}}==
{{works with|Rhino}}
{{works with|SpiderMonkey}}
<syntaxhighlight lang="javascript">var s1 = "Hello";
s1 += ", World!";
print(s1);

var s2 = "Goodbye";
// concat() returns the strings together, but doesn't edit existing string
// concat can also have multiple parameters
print(s2.concat(", World!"));</syntaxhighlight>
{{out}}
<pre>
"Hello, World!"
"Goodbye, World!"
</pre>

=={{header|jq}}==
jq's <code>+</code> operator can be used to append two strings, and under certain circumstances the <code>+=</code> operator can be used as an abbreviation for appending a string to an existing string.  For example, all three of the following produce the same output:<syntaxhighlight lang="jq">"Hello" | . += ", world!"

["Hello"] | .[0] += ", world!" | .[0]

{ "greeting": "Hello"} | .greeting += ", world!" | .greeting</syntaxhighlight>
However the <code>+=</code> operator cannot be used with jq variables in the conventional manner. One could nevertheless use the technique illustrated by the following:<syntaxhighlight lang="jq">"Hello" as $a | $a | . += ", world!" as $a | $a</syntaxhighlight>

=={{header|Jsish}}==
From Javascript entry.
<syntaxhighlight lang="javascript">/* String append, in Jsish */
var str = 'Hello';
;str += ', world';

var s2 = 'Goodbye';
;s2.concat(', World!');

/*
=!EXPECTSTART!=
str += ', world' ==> Hello, world
s2.concat(', World!') ==> Goodbye, World!
=!EXPECTEND!=
*/</syntaxhighlight>

{{out}}
<pre>prompt$ jsish --U stringAppend.jsi
str += ', world' ==> Hello, world
s2.concat(', World!') ==> Goodbye, World!</pre>

=={{header|Julia}}==
<syntaxhighlight lang="julia">s = "Hello"
s *= ", world!"</syntaxhighlight>
{{out}}
<pre>"Hello, world!"</pre>

=={{header|K}}==
<syntaxhighlight lang=K>h: "hello "
h,: "world"
h
"hello world"</syntaxhighlight>
=={{header|Kotlin}}==
<syntaxhighlight lang="kotlin">fun main(args: Array<String>) {
    var s = "a"
    s += "b"
    s += "c"
    println(s)
    println("a" + "b" + "c")
    val a = "a"
    val b = "b"
    val c = "c"
    println("$a$b$c")
}</syntaxhighlight>
{{out}}
<pre>abc
abc
abc</pre>

=={{header|Lambdatalk}}==
In Lambdatalk writing {def name a sequence of words} replaces the sequence of words by the given name in the code string. The name is a word and is not evaluated. Bracketing a name between two curly braces returns its related value. And concatenating named strings is simply done by writing names between curly braces and separated by spaces. 
<syntaxhighlight lang="scheme">
{def christian_name Albert}
-> christian_name
{def name de Jeumont-Schneidre}
-> name

{christian_name} {name}
-> Albert de Jeumont-Schneidre
</syntaxhighlight>

=={{header|Lang}}==
<syntaxhighlight lang="lang">
$s = Hello
$s += \, World!

fn.println($s)
</syntaxhighlight>
{{out}}
<pre>
Hello World
</pre>

=={{header|langur}}==
<syntaxhighlight lang="langur">var .s = "no more "
.s ~= "foo bars"
writeln .s</syntaxhighlight>

{{out}}
<pre>no more foo bars</pre>

=={{header|Lasso}}==
<syntaxhighlight lang="lasso">local(x = 'Hello')
#x->append(', World!')
#x</syntaxhighlight>
{{out}}
<pre>Hello, World!</pre>

=={{header|LDPL}}==
<syntaxhighlight lang="ldpl">data:
myText is text

procedure:
store "LD" in myText
in myText join myText "PL"
display myText lf
</syntaxhighlight>
{{out}}
<pre>
LDPL
</pre>

=={{header|Lingo}}==
<syntaxhighlight lang="lingo">str = "Hello" 
put " world!" after str
put str
-- "Hello world!"</syntaxhighlight>

=={{header|LiveCode}}==
Livecode has an "after" keyword for this
<syntaxhighlight lang="livecode">local str="live"
put "code" after str</syntaxhighlight>
Output is "livecode"

=={{header|Lua}}==
Not possible as strings are immutable.  We can demonstrate their immutability using 'self':
<syntaxhighlight lang="lua">function string:show ()
    print(self)
end

function string:append (s)
    self = self .. s
end

x = "Hi "
x:show()
x:append("there!")
x:show()</syntaxhighlight>
{{out}}
<pre>Hi 
Hi </pre>
You can of course concatentate them and store the result in the original variable name but that requires a double reference:
<syntaxhighlight lang="lua">x = "Hi "
x = x .. "there!"
print(x)</syntaxhighlight>
{{out}}
<pre>Hi there!</pre>

=={{header|M2000 Interpreter}}==
Documents in M2000 are objects with paragraphs. From Version 12 we can use variable names for strings without suffix $, although a and a$ are different variable names.

<syntaxhighlight lang="m2000 interpreter">
a="ok"
a+="(one)"
Print a

a$="ok"
a$+="(one)"
Print a$

Document b$
b$="ok"
b$="(one)"
Print b$ 
</syntaxhighlight>
{{out}}
<pre>ok(one)
ok(one)
</pre>

=={{header|Maple}}==
<syntaxhighlight lang="maple">a := "Hello";
b := cat(a, " World");
c := `||`(a, " World");</syntaxhighlight>
{{out}}
<pre>
                            "Hello"
                         "Hello World"
                         "Hello World"
</pre>

=={{header|Mathematica}}/{{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">(* mutable strings are not supported *)
s1 = "testing";
s1 = s1 <> " 123";
s1</syntaxhighlight>
{{out}}
<pre>"testing 123"</pre>

=={{header|min}}==
{{works with|min|0.19.6}}
<syntaxhighlight lang="min">(quote cons "" join) :str-append

"foo" "bar" str-append puts!</syntaxhighlight>
{{out}}
<pre>
foobar
</pre>

=={{header|MiniScript}}==
<syntaxhighlight lang="miniscript">
s1 = "Hello"
s1 = s1 + ", "
s1 += "World!"
print s1
</syntaxhighlight>
{{out}}
<pre>
Hello, World!
</pre>

=={{header|MontiLang}}==
<syntaxhighlight lang="montilang">|Hello | |world!| swap + print</syntaxhighlight>
<syntaxhighlight lang="montilang">|Hello | var hello .
|world!| var world .
world hello + print</syntaxhighlight>

=={{header|Nanoquery}}==
<syntaxhighlight lang="nanoquery">s1 = "this is"
s1 += " a test"

println s1</syntaxhighlight>

{{out}}
<pre>this is a test</pre>

=={{header|Neko}}==
The plus operator +, concats strings.
 
<syntaxhighlight lang="actionscript">/**
 <doc><p>String append in Neko</pre></doc>
**/

var str = "Hello"
str += ", world"
$print(str, "\n")</syntaxhighlight>
{{out}}
<pre>prompt$ nekoc string-append.neko
prompt$ neko ./string-append.n
Hello, world</pre>

=={{header|NetRexx}}==
<syntaxhighlight lang="netrexx">s_ = 'Hello'
s_ = s_', world!'
say s_</syntaxhighlight>
{{out}}
<pre>
Hello, world!
</pre>

=={{header|NewLISP}}==
<syntaxhighlight lang="newlisp">(setq str "foo")

(push "bar" str -1)
; or as an alternative introduced in v.10.1
(extend str "bar")

(println str)
</syntaxhighlight>

=={{header|Nim}}==
<syntaxhighlight lang="nim">var str = "123456"
str.add("78") # Using procedure "add".
str &= "9!"   # Using operator "&=".
echo str
</syntaxhighlight>

{{out}}
<pre>123456789!</pre>

=={{header|NS-HUBASIC}}==
<syntaxhighlight lang="ns-hubasic">10 S$ = "HELLO"
20 S$ = S$ + " WORLD!"
30 PRINT S$</syntaxhighlight>

=={{header|Objeck}}==
<syntaxhighlight lang="objeck">
class Append {
  function : Main(args : String[]) ~ Nil {
    x := "foo";
    x->Append("bar");
    x->PrintLine();
  }
}
</syntaxhighlight>

=={{header|OCaml}}==
<syntaxhighlight lang="ocaml">let () =
  let s = Buffer.create 17 in
  Buffer.add_string s "Bonjour";
  Buffer.add_string s " tout le monde!";
  print_endline (Buffer.contents s)</syntaxhighlight>
{{out}}
<pre>Bonjour tout le monde!</pre>

=={{header|Oforth}}==

<syntaxhighlight lang="oforth">StringBuffer new "Hello, " << "World!" << println</syntaxhighlight>

=={{header|PARI/GP}}==
Not supported in GP.
<syntaxhighlight lang="parigp">s = "Hello";
s = Str(s, ", world!")</syntaxhighlight>
{{out}}
<pre>%1 = "Hello, world!"</pre>

=={{header|Pascal}}==

{{works with|Free Pascal|2.6.2}}

<syntaxhighlight lang="pascal">program StringAppend;
{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes
  { you can add units after this };

var
    s: String = 'Hello';
begin
  s += ' World !';
  WriteLn(S);
  ReadLn;
end.</syntaxhighlight>
Output:
<pre>Hello  World !</pre>

=={{header|Perl}}==
<syntaxhighlight lang="perl">my $str = 'Foo';
$str .= 'bar';
print $str;</syntaxhighlight>
{{out}}
<pre>Foobar</pre>

=={{header|Phix}}==
{{libheader|Phix/basics}}
<!--<syntaxhighlight lang="phix">-->
 <span style="color: #004080;">string</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"this string"</span>        <span style="color: #0000FF;">?</span><span style="color: #000000;">s</span>
 <span style="color: #000000;">s</span> <span style="color: #0000FF;">&=</span> <span style="color: #008000;">" is now longer"</span>           <span style="color: #0000FF;">?</span><span style="color: #000000;">s</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
"this string"
"this string is now longer"
</pre>

=={{header|Phixmonti}}==
<syntaxhighlight lang="Phixmonti">/# Rosetta Code problem: https://rosettacode.org/wiki/String_append
by Galileo, 11/2022 #/

"Hello" var s
s " world" chain var s
s print
</syntaxhighlight>
{{out}}
<pre>Hello world
=== Press any key to exit ===</pre>

=={{header|Picat}}==
<syntaxhighlight lang="picat">main =>
  S = "a string",
  S := S + " that is longer",
  println(S).</syntaxhighlight>

{{out}}
<pre>a string that is longer</pre>


=={{header|PicoLisp}}==
<syntaxhighlight lang="picolisp">(setq Str1 "12345678")
(setq Str1 (pack Str1 "9!"))
(println Str1)</syntaxhighlight>
{{out}}
<pre>"123456789!"</pre>

=={{header|Pike}}==
<syntaxhighlight lang="pike">
string msg = "hello";
msg += " world";
write(msg +"\n");
</syntaxhighlight>
{{Out}}
<pre>
hello world
</pre>

=={{header|PL/I}}==
<syntaxhighlight lang="pl/i">Cat: procedure options (main);
   declare s character (100) varying;
   s = 'dust ';
   s ||= 'bowl';
   put (s);
end Cat;</syntaxhighlight>
<pre>dust bowl</pre>

=={{header|Plain English}}==
<syntaxhighlight lang="plainenglish">To run:
Start up.
Put "abc" into a string.
Append "123" to the string.
Write the string to the console.
Wait for the escape key.
Shut down.</syntaxhighlight>
{{out}}
<pre>
abc123
</pre>

=={{header|plainTeX}}==
Works with any TeX engine
<syntaxhighlight lang="tex">\def\addtomacro#1#2{\expandafter\def\expandafter#1\expandafter{#1#2}}
\def\foo{Hello}
Initial: \foo

\addtomacro\foo{ world!}
Appended: \foo
\bye</syntaxhighlight>

pdf or dvi output:
<pre>Initial: Hello
Appended: Hello world!
</pre>

=={{header|PowerShell}}==
<syntaxhighlight lang="powershell">
$str = "Hello, "
$str += "World!"
$str
</syntaxhighlight>
<pre>Hello, World!</pre>

=={{header|PureBasic}}==
<syntaxhighlight lang="purebasic">S$ = "Hello"
S$ = S$ + " Wo" ;by referencing the string twice
S$ + "rld!"     ;by referencing the string once
If OpenConsole()
  PrintN(S$)

  Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
  CloseConsole()
EndIf</syntaxhighlight>
Sample output:
<pre>Hello World!</pre>

=={{header|Python}}==
'''File: String_append.py'''<syntaxhighlight lang="python">#!/usr/bin/env python
# -*- coding: utf-8 -*- #

str = "12345678";
str += "9!";
print(str)</syntaxhighlight>
{{out}}
<pre>
123456789!
</pre>

=={{header|QB64}}==
<syntaxhighlight lang="qbasic">s$ = "String"
s$ = s$ + " append"
Print s$</syntaxhighlight>
{{out}}
<pre>String append</pre>

=={{header|Quackery}}==

Quackery has no variables. The nearest equivalent is ''ancillary stacks''. The word <code>join</code> will return the concatenation of two nests on the stack, and hence two strings, as strings are a particular usage of nests. Here we define the word <code>append</code> to join a nest on the stack to a nest on an ancillary stack, and then demonstrate its use with a Jules Renard quotation and the predefined ancillary stack <code>temp</code>.

<syntaxhighlight lang="quackery">  [ tuck take swap join swap put ] is append ( [ s --> )
  
  $ "L'homme qui attend de voir un canard roti voler "   temp put
  $ "dans sa bouche doit attendre tres, tres longtemps." temp append
  temp take echo$ </syntaxhighlight>

{{out}}

<pre>L'homme qui attend de voir un canard roti voler dans sa bouche doit attendre tres, tres longtemps.</pre>

=={{header|Racket}}==
<syntaxhighlight lang="racket">;there is no built-in way to set! append in racket
(define mystr "foo")
(set! mystr (string-append mystr " bar"))
(displayln mystr)

;but you can create a quick macro to solve that problem
(define-syntax-rule (set-append! str value)
  (set! str (string-append str value)))

(define mymacrostr "foo")
(set-append! mymacrostr " bar")
(displayln mystr)</syntaxhighlight>

{{out}}
<pre>
foo bar
foo bar
</pre>

=={{header|Raku}}==
(formerly Perl 6)
<syntaxhighlight lang="raku" line>my $str = "foo";
$str ~= "bar";
say $str;</syntaxhighlight>
{{out}}
<pre>foobar</pre>

=={{header|Relation}}==
<syntaxhighlight lang="relation">
set a = "Hello"
set b = " World"
set c = a.b
echo c
</syntaxhighlight>

=={{header|REXX}}==
===using abutment===
<syntaxhighlight lang="rexx">s='he'
s=s'llo world!'
Say s</syntaxhighlight>
'''output'''
<pre>
hello world!
</pre>

===using concatenation===
<syntaxhighlight lang="rexx">s="He"
s=s || 'llo, World!'       /*same as:   s=s||'llo, World!'    */
say s</syntaxhighlight> 
'''output'''
<pre>
Hello, World!
</pre>

=={{header|Ring}}==
<syntaxhighlight lang="ring">
aString1 = "Welcome to the "
aString2 = "Ring Programming Language"
aString3 = aString1 + aString2
see aString3
</syntaxhighlight>

=={{header|Robotic}}==
<syntaxhighlight lang="robotic">
set "$str1" to "Hello "
inc "$str1" by "world!"
* "&$str1&"
end
</syntaxhighlight>

=={{header|RPL}}==
In HP-48+ RPL versions, the <code>STO+</code> instruction can append a string to a variable containing already a string.
 "def" '<span style="color:green">Z</span>' STO
 '<span style="color:green">Z</span>' "ghi" STO+
 <span style="color:green">Z</span>
'''Output'''
 <span style="color:grey"> 1:</span> "defghi"

=={{header|Ruby}}==
<syntaxhighlight lang="ruby">s = "Hello wo"
s += "rld" # new string object
s << "!"   # mutates in place, same object
puts s</syntaxhighlight>
{{out}}<pre>Hello world!</pre>

=={{header|Rust}}==
<syntaxhighlight lang="rust">
use std::ops::Add;

fn main(){
    let hello = String::from("Hello world");
    println!("{}", hello.add("!!!!"));
}</syntaxhighlight>
{{out}}
Hello world!!!!

=== Real append ===
The first solution doesn't append to the string variable. This solution really appends to the existing variable.
<syntaxhighlight lang="rust">
fn main(){
    let mut hello = String::from("Hello world");
    hello.push_str("!!!!");
    println!("{}", hello);
}
</syntaxhighlight>
{{out}}
Hello world!!!!

=={{header|Scala}}==
An evaluation in Scala worksheet.
<syntaxhighlight lang="scala">  var d = "Hello" // Mutables are discouraged     //> d  : String = Hello
  d += ", World!" // var contains a totally new re-instantiationed String

  val s = "Hello" // Immutables are recommended   //> s  : String = Hello
  val s1 = s + s                                  //> s1  : String = HelloHello
  val f2 = () => " !" //Function assigned to variable
                                                  //> f2  : () => String = <function0>
  println(s1 + f2());                             //> HelloHello !</syntaxhighlight>

=={{header|sed}}==
There are no variables in ''sed'', just two distinct locations for storing a string: The "pattern space" and the "hold space".
* The <code>H</code> command appends the content of pattern space to the hold space.
* The <code>G</code> command appends the content of hold space to the pattern space.
* The <code>N</code> command appends the next input line to the pattern space.
All three commands insert a newline character between both strings during appending. In pattern space, it can be removed afterwards with the <code>s</code> command, like this:
<syntaxhighlight lang="sed">N
s/\n//</syntaxhighlight>
* The <code>s</code> command can also be used to append a string literal to the pattern space:
<syntaxhighlight lang="sed">s/$/String Literal/</syntaxhighlight>
* To append further lines to the output (after the printing of the pattern space), the <code>a</code> command is useful:
<syntaxhighlight lang="sed">a\
one more line\
and another one</syntaxhighlight>

=={{header|Seed7}}==
<syntaxhighlight lang="seed7">$ include "seed7_05.s7i";

const proc: main is func
  local
    var string: str is "12345678";
  begin
    str &:= "9!";
    writeln(str);
  end func;</syntaxhighlight>

{{out}}
<pre>
123456789!
</pre>

=={{header|Sidef}}==
<syntaxhighlight lang="ruby">var str = 'Foo';
str += 'bar';
say str;</syntaxhighlight>
{{out}}
<pre>Foobar</pre>

=={{header|SNOBOL4}}==
<syntaxhighlight lang="snobol4">     s = "Hello"
     s = s ", World!"
     OUTPUT = s
END</syntaxhighlight>
{{out}}
<pre>Hello, World!</pre>

=={{header|Stata}}==
<syntaxhighlight lang="stata">sca s="Ars Longa"
sca s=s+" Vita Brevis"
di s

Ars Longa Vita Brevis</syntaxhighlight>

=={{header|Swift}}==
<syntaxhighlight lang="swift">var s = "foo"              // "foo"
s += "bar"                 // "foobar"
print(s)                   // "foobar"
s.appendContentsOf("baz")  // "foobarbaz"
print(s)                   // "foobarbaz"</syntaxhighlight>

=={{header|Tcl}}==
String concatenation is a fundamental feature of the Tcl language, and there is also an <code>append</code> that makes concatenation even simpler:
<syntaxhighlight lang="tcl">set s "he"
set s "${s}llo wo";   # The braces distinguish varname from text to concatenate
append s "rld"
puts $s</syntaxhighlight>
{{out}}<pre>hello world</pre>

=={{header|Transd}}==
<syntaxhighlight lang="scheme">#lang transd

MainModule: {
    _start: (λ 
        (with s1 "aaa" s2 "bbb" s3 "ccc"
            (+= s1 s2 s3) 
            (textout s1))
    )
}</syntaxhighlight>
{{out}}
<pre>
aaabbbccc
</pre>

=={{header|Ursa}}==
<syntaxhighlight lang="ursa">decl string str
set str "hello "

# append "world" to str
set str (+ str "world")

# outputs "hello world"
out str endl console</syntaxhighlight>

=={{header|Vala}}==
<syntaxhighlight lang="vala">void main() {
  string x = "foo";
  x += "bar\n";
  print(x);
}</syntaxhighlight>

=={{header|VBA}}==
<syntaxhighlight lang="vb">Function StringAppend()
Dim s As String
s = "foo"
s = s & "bar"
Debug.Print s
End Function</syntaxhighlight>

=={{header|VBScript}}==
<syntaxhighlight lang="vb">s = "Rosetta"
s = s & " Code"
WScript.StdOut.Write s</syntaxhighlight>
{{out}}
<pre>Rosetta Code</pre>

=={{header|V (Vlang)}}==
<syntaxhighlight lang="v (vlang)">mut s:= 'foo'
s += 'bar'
println(s)

foo := 'foo'
bar := 'bar'
foobar := '$foo$bar'
println(foobar)</syntaxhighlight>

{{out}}
<pre>foobar
foobar
</pre>

=== String Builder ===
TODO

=={{header|Wart}}==
<syntaxhighlight lang="python">s <- "12345678"
s <- (s + "9!")</syntaxhighlight>

=={{header|Wren}}==
<syntaxhighlight lang="wren">var s = "Hello, "
s = s + "world!"
System.print(s)</syntaxhighlight>

{{out}}
<pre>
Hello, world!
</pre>

=={{header|XPL0}}==
<syntaxhighlight lang="xpl0">include xpllib;
char A, B, C(80);
[A:= "Hello, ";
B:= "world!";
StrCopy(C, A);
StrCat(C, B);
Text(0, C);
]</syntaxhighlight>

{{out}}
<pre>
Hello, world!
</pre>

=={{header|zkl}}==
zkl strings are immutable, but byte blobs are mutable.
<syntaxhighlight lang="zkl">var s="foo";
s.append("bar"); //-->new string "foobar", var s unchanged
s+="bar";        //-->new string "foobar", var s modifed to new value

s=Data(Void,"foo");	// byte blob/character blob/text editor buffer
s.append("bar");  // or s+="bar"
s.text; //-->"foobar"</syntaxhighlight>

{{omit from|bc|No string operations in bc}}
{{omit from|dc|No string operations in dc}}