Swap two variables
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[edit] Implementation
[edit] C++
#include <algorithm> std::swap(a, b);
[edit] Go
a, b = b, a
[edit] OCaml
OCaml variables are immutable, so we can only create a new local binding
let a, b = b, a in (* do stuff here *)
[edit] Perl
($a, $b) = ($b, $a);
[edit] PHP
// Test variables $a = "content a"; $b = "content b"; // Swap $a and $b list($a, $b) = array($b, $a); // Debug print print "variable a: $a\n"; print "variable b: $b\n"; /* Output: variable a: content b variable b: content a */
[edit] Python
a, b = b, a
[edit] Ruby
a, b = b, a
[edit] WinBatch
; Swap two variables. ; Example 1. Dim-1 array. arrSwapEx1 = ArrDimension (4) arrSwapEx1 [0] = 1 arrSwapEx1 [1] = 2 ; <== arrSwapEx1 [2] = 3 arrSwapEx1 [3] = 4 ; <== ArraySwapElements (arrSwapEx1, 1, 0, 0, 0, 0, 3, 0, 0, 0, 0) ; Result ; arrSwapEx1 [0] = 1 ; arrSwapEx1 [1] = 4 ; <== ; arrSwapEx1 [2] = 3 ; arrSwapEx1 [3] = 2 ; <== ; Example 2. Dim-2 array. arrSwapEx2 = ArrDimension (2, 3) arrSwapEx2 [0, 0] = 10 arrSwapEx2 [0, 1] = 11 ; <== arrSwapEx2 [0, 2] = 12 arrSwapEx2 [1, 0] = 20 arrSwapEx2 [1, 1] = 21 arrSwapEx2 [1, 2] = 22 ; <== ArraySwapElements (arrSwapEx2, 0, 1, 0, 0, 0, 1, 2, 0, 0, 0) ; Result ; arrSwapEx2 [0,0] = 10 ; arrSwapEx2 [0,1] = 22 ; <== ; arrSwapEx2 [0,2] = 12 ; arrSwapEx2 [1,0] = 20 ; arrSwapEx2 [1,1] = 21 ; arrSwapEx2 [1,2] = 11 ; <== ; Example 3. Dim-3 array. arrSwapEx3 = ArrDimension (2, 3, 2) arrSwapEx3 [0, 0, 0] = 1 arrSwapEx3 [0, 0, 1] = "" arrSwapEx3 [0, 1, 0] = "" arrSwapEx3 [0, 1, 1] = "Hello" ; <== arrSwapEx3 [0, 2, 0] = "" arrSwapEx3 [0, 2, 1] = "" arrSwapEx3 [1, 0, 0] = "" arrSwapEx3 [1, 0, 1] = "" arrSwapEx3 [1, 1, 0] = "" arrSwapEx3 [1, 1, 1] = "World" ; <== arrSwapEx3 [1, 2, 0] = "" arrSwapEx3 [1, 2, 1] = 12 ArraySwapElements (arrSwapEx3, 1, 2, 1, 0, 0, 0, 0, 0, 0, 0) ; 1. ArraySwapElements (arrSwapEx3, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0) ; 2. ; Result ; arrSwapEx3 [0,0,0] = 12 ; <== 1. ; arrSwapEx3 [0,0,1] = "" ; arrSwapEx3 [0,1,0] = "" ; arrSwapEx3 [0,1,1] = "World" ; <== 2. ; arrSwapEx3 [0,2,0] = "" ; arrSwapEx3 [0,2,1] = "" ; arrSwapEx3 [1,0,0] = "" ; arrSwapEx3 [1,0,1] = "" ; arrSwapEx3 [1,1,0] = "" ; arrSwapEx3 [1,1,1] = "Hello" ; <== 2. ; arrSwapEx3 [1,2,0] = "" ; arrSwapEx3 [1,2,1] = 1 ; <== 1. ; Syntax ; ArraySwapElements (array, subA1, subA2, subA3, subA4, subA5, subB1, subB2, subB3, subB4, subB5) ; "subA1" to "subA5" specify the subscripts of element "A". ; "subB1" to "subB5" specify the subscripts of element "B". ; Example 4. Integer variables. ; Set content. intA = 1 intB = 2 ; Swap content. intTemp = intA intA = intB intB = intTemp Drop (intTemp) ; Temporary variable can be dropped after swapping. ; Result ; intA = 2 ; intB = 1 ; Example 5. String variables. ; Set content. strA = "Hello" strB = "World" ; Swap content. strTemp = strA strA = strB strB = strTemp Drop (strTemp) ; Temporary variable can be dropped after swapping. ; Result ; strA = "World" ; strB = "Hello" Exit ; This code example was written by Detlev Dalitz.20090706.2130.CEST
