String append

From Rosetta Code
Task
String append
You are encouraged to solve this task according to the task description, using any language you may know.

Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.

You may see other such operations in the Basic Data Operations category, or:

Integer Operations
Arithmetic | Comparison

Boolean Operations
Bitwise | Logical

String Operations
Concatenation | Interpolation | Comparison | Matching

Memory Operations
Pointers & references | Addresses

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.

Ada

<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; </lang>

Output:
Hello, world!

ALGOL 68

Works with: ALGOL 68 version Revision 1.
Works with: ALGOL 68G version Any - tested with release algol68g-2.7.
Works with: ELLA ALGOL 68 version Any (with appropriate job cards).

File: String_append.a68<lang algol68>#!/usr/bin/a68g --script #

  1. -*- coding: utf-8 -*- #

STRING str := "12345678"; str +:= "9!"; print(str)</lang>

Output:
123456789!

AutoHotkey

<lang autohotkey>s := "Hello, " s .= "world." MsgBox % s</lang>

Output:
Hello, world.

AWK

<lang AWK>

  1. syntax: GAWK -f STRING_APPEND.AWK

BEGIN { 

   s = "foo"
   s = s "bar"
   print(s)
   exit(0)

} </lang>

Output:
foobar

Axe

<lang axe>Lbl STRCAT Copy(r₂,r₁+length(r₁),length(r₂)+1) r₁ Return</lang>

BASIC

Applesoft BASIC

<lang BASIC>S$ = "Hello" S$ = S$ + " World!" PRINT S$</lang>

BBC BASIC

<lang BBC BASIC> S$="Hello" 

     S$+=" World!"
     PRINT S$
     END</lang>
Output:
Hello World!

IS-BASIC

<lang IS-BASIC>100 LET S$="Hello" 110 LET S$=S$&" World!" 120 PRINT S$</lang>

Bracmat

<lang Bracmat>str="Hello"; str$(!str " World!"):?str; out$!str;</lang>

Output:
Hello World!

C

<lang c>#include<stdio.h>

  1. 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;

}</lang>

Output:
Good Morning to all !!!

C++

<lang cpp>#include <iostream>

  1. include <string>

int main( ) { 

  std::string greeting( "Hello" ) ;
  greeting.append( " , world!" ) ;
  std::cout << greeting << std::endl ;
  return 0 ;

}</lang>

Output:
Hello , world!

C#

<lang csharp>class Program { 

   static void Main(string[] args)
   {
       string x = "foo";
       x += "bar";
       System.Console.WriteLine(x);
   }

}</lang>

Clojure

Using global vars. <lang clojure>user=> (def s "app")

  1. 'user/s

user=> s "app" user=> (def s (str s "end"))

  1. 'user/s

user=> s "append"</lang>

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

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

<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.

</lang>

Output:
$ cobc -xj string-append.cob
Hello, world

CoffeeScript

Works with: Node.js

<lang coffeescript>a = "Hello, " b = "World!" c = a + b

console.log c</lang> Or with concat: <lang coffeescript>console.log "Hello, ".concat "World!"</lang>

Output:
Hello, World!

Common Lisp

Similar to the Racket solution, a macro is necessary to append in-place: <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*)</lang>

Output: 

foobar
foobarbazabcdef

D

<lang d>import std.stdio;

void main() { 

   string s = "Hello";
   s ~= " world!"; 
   writeln(s);

}</lang>

Output:
Hello world!

EchoLisp

<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"

</lang>

Elena

ELENA 3.4 : <lang elena>import extensions. import extensions'text.

public program [ 

   var s := String new:"Hello".
   s append:" World".

   console writeLine:s; readChar.

]</lang>

Elixir

<lang elixir>iex(60)> s = "Hello" "Hello" iex(61)> s <> " World!" "Hello World!"</lang>

Emacs Lisp

version 1

<lang Emacs Lisp> (defun glue (str1 str2) 

 (concat str1 str2) )

</lang>

version 2

<lang Emacs Lisp> (defun glue (str1 str2) 

 (format "%s%s" str1 str2) )

</lang> Eval: <lang Emacs Lisp> (setq str "Hello, ") (setq str (glue str "World!") ) (insert str) </lang> Output: 

Hello, World!


Erlang

Output:
1> S = "Hello".
"Hello"
2> S ++ " world".
"Hello world"


Euphoria

<lang euphoria> sequence string = "String"

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

string &= " is now longer\n"

printf(1,"%s",{string}) </lang>

Output:
String
String is now longer

F#

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

Factor

<lang factor>"Hello, " "world!" append</lang>

Output:
"Hello, world!"


Falcon

<lang falcon> /* Added by Aykayayciti Earl Lamont Montgomery April 10th, 2018 */

s1, s2 = "Hello", "Foo" > s1 + " World" printl(s2 + " bar") </lang>

Output:
Hello World
Foo bar
[Finished in 0.2s]

Forth

<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"</lang>

Test at the console

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

Fortran

Using deferred length character strings:

<lang Fortran> program main 

character(len=:),allocatable :: str

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

write(*,*) str

end program main </lang>

FreeBASIC

<lang freebasic>' FB 1.05.0 Win64

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

Output:
String append

Gambas

Click this link to run this code <lang gambas>Public Sub Main() Dim sString As String = "Hello "

sString &= "World!" Print sString

End</lang> Output: 

Hello World!

GlovePIE

<lang glovepie>var.string="This is " var.string+="Sparta!" debug=var.string</lang>

Go

<lang go>s := "foo" s += "bar"</lang>

Gosu

<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}")</lang>

Output:
abc
abc
abc

Icon and Unicon

In both languages you can:

<lang unicon> procedure main() 

   s := "foo"
   s ||:= "bar"
   write(s)

end </lang>

Outputs: 

->ss
foobar
->

Groovy

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

Output:
Hello world

Haskell

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

J

<lang j> s=: 'new' 

  s

new 

  s=: s,' value'   NB. append is in-place
  s

new value</lang>

Java

<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());</lang>

Output:
Hello, World!
Hello, World!

JavaScript

Works with: Rhino
Works with: SpiderMonkey

<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!"));</lang>

Output:
"Hello, World!"
"Goodbye, World!"

jq

jq's + operator can be used to append two strings, and under certain circumstances the += 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:<lang jq>"Hello" | . += ", world!"

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

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

Julia

<lang julia>s = "Hello" s *= ", world!"</lang>

Output:
"Hello, world!"

Kotlin

<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")

}</lang>

Output:
abc
abc
abc

Lasso

<lang Lasso>local(x = 'Hello')

  1. x->append(', World!')
  2. x</lang>
Output:
Hello, World!

Lingo

<lang lingo>str = "Hello" put " world!" after str put str -- "Hello world!"</lang>

LiveCode

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

Lua

Not possible as strings are immutable. We can demonstrate their immutability using 'self': <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()</lang>

Output:
Hi 
Hi

You can of course concatentate them and store the result in the original variable name but that requires a double reference: <lang Lua>x = "Hi " x = x .. "there!" print(x)</lang>

Output:
Hi there!

M2000 Interpreter

Documents in M2000 are objects with paragraphs.

<lang M2000 Interpreter> a$="ok" a$+="(one)" Print a$

Document b$ b$="ok" b$="(one)" Print b$ </lang>

Output:
ok(one)
ok(one)

Maple

<lang maple>a := "Hello"; b := cat(a, " World"); c := `||`(a, " World");</lang>

Output:
                            "Hello"
                         "Hello World"
                         "Hello World"

Mathematica

<lang Mathematica> (* mutable strings are not supported *) s1 = "testing"; s1 = s1 <> " 123"; s1</lang>

Output:
"testing 123"

NetRexx

<lang NetRexx>s_ = 'Hello' s_ = s_', world!' say s_</lang>

Output:
Hello, world!

NewLISP

<lang NewLISP>(setq str "foo")

(push "bar" str -1)

or as an alternative introduced in v.10.1

(extend str "bar")

(println str) </lang>

Nim

<lang nim>var str = "123456" str.add("78") # two ways str &= "9!" # to append</lang>

Objeck

<lang objeck> class Append { 

 function : Main(args : String[]) ~ Nil {
   x := "foo";
   x->Append("bar");
   x->PrintLine();
 }

} </lang>

OCaml

<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)</lang>
Output:
Bonjour tout le monde!


Oforth

<lang Oforth>StringBuffer new "Hello, " << "World!" << println</lang>

PARI/GP

Not supported in GP. <lang parigp>s = "Hello"; s = Str(s, ", world!")</lang>

Output:
%1 = "Hello, world!"

Pascal

Works with: Free Pascal version 2.6.2

<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.</lang> Output: 

Hello  World !

Perl

<lang perl>my $str = 'Foo'; $str .= 'bar'; print $str;</lang>

Output:
Foobar

Perl 6

<lang perl6>my $str = "foo"; $str ~= "bar"; say $str;</lang>

Output:
foobar

Phix

<lang Phix>string s = "this string" ?s s &= " is now longer" ?s</lang>

Output:
"this string"
"this string is now longer"

PicoLisp

<lang picolisp>(setq Str1 "12345678") (setq Str1 (pack Str1 "9!")) (println Str1)</lang>

Output:
"123456789!"

PL/I

<lang PL/I>Cat: procedure options (main); 

  declare s character (100) varying;
  s = 'dust ';
  s ||= 'bowl';
  put (s);

end Cat;</lang> 

dust bowl


Plain TeX

Works with any TeX engine <lang tex>\def\addtomacro#1#2{\expandafter\def\expandafter#1\expandafter{#1#2}} \def\foo{Hello} Initial: \foo

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

pdf or dvi output: 

Initial: Hello
Appended: Hello world!

PowerShell

<lang PowerShell> $str = "Hello, " $str += "World!" $str </lang> 

Hello, World!

PureBasic

<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</lang> Sample output: 

Hello World!

Python

File: String_append.py<lang python>#!/usr/bin/env python

  1. -*- coding: utf-8 -*- #

str = "12345678"; str += "9!"; print(str)</lang>

Output:
123456789!

Racket

<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)</lang>

Output:
foo bar
foo bar

REXX

using abutment

<lang rexx>s='he' s=s'llo world!' Say s</lang> output 

hello world!

using concatenation

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

Hello, World!

Ring

<lang ring> aString1 = "Welcome to the " aString2 = "Ring Programming Language" aString3 = aString1 + aString2 see aString3 </lang>

Ruby

<lang ruby>s = "Hello wo" s += "rld" # new string object s << "!" # mutates in place, same object puts s</lang>

Output:
Hello world!


Rust

<lang rust> use std::ops::Add;

fn main(){ 

   let hello = String::from("Hello world");
   println!("{}", hello.add("!!!!"));

}</lang>

Output:

Hello world!!!!

Scala

An evaluation in Scala worksheet. <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 !</lang>

Seed7

<lang seed7>$ include "seed7_05.s7i";

const proc: main is func 

 local
   var string: str is "12345678";
 begin
   str &:= "9!";
   writeln(str);
 end func;</lang>
Output:
123456789!

Sidef

<lang ruby>var str = 'Foo'; str += 'bar'; say str;</lang>

Output:
Foobar

SNOBOL4

<lang SNOBOL4> s = "Hello" 

    s = s ", World!"
    OUTPUT = s

END</lang>

Output:
Hello, World!

Stata

<lang stata>sca s="Ars Longa" sca s=s+" Vita Brevis" di s

Ars Longa Vita Brevis</lang>

Swift

<lang swift>var s = "foo" // "foo" s += "bar" // "foobar" print(s) // "foobar" s.appendContentsOf("baz") // "foobarbaz" print(s) // "foobarbaz"</lang>

Tcl

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

Output:
hello world

Ursa

<lang ursa>decl string str set str "hello "

  1. append "world" to str

set str (+ str "world")

  1. outputs "hello world"

out str endl console</lang>

VBA

<lang VB>Function StringAppend() Dim s As String s = "foo" s = s & "bar" Debug.Print s End Function</lang>

VBScript

<lang vb>s = "Rosetta" s = s & " Code" WScript.StdOut.Write s</lang>

Output:
Rosetta Code

Wart

<lang python>s <- "12345678" s <- (s + "9!")</lang>

zkl

zkl strings are immutable, but byte blobs are mutable. <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"</lang>

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