"is there a php function for swapping the values of two variables?" Answer’s

0

TL;DR

There isn't a built-in function. Use swap3() as mentioned below.

Summary

As many mentioned, there are multiple ways to do this, most noticable are these 4 methods:

function swap1(&$x, &$y) {
    // Warning: works correctly with numbers ONLY!
    $x ^= $y ^= $x ^= $y;
}
function swap2(&$x, &$y) {
    list($x,$y) = array($y, $x);
}
function swap3(&$x, &$y) {
    $tmp=$x;
    $x=$y;
    $y=$tmp;
}
function swap4(&$x, &$y) {
    extract(array('x' => $y, 'y' => $x));
}

I tested the 4 methods under a for-loop of 1000 iterations, to find the fastest of them:

  • swap1() = scored approximate average of 0.19 seconds.
  • swap2() = scored approximate average of 0.42 seconds.
  • swap3() = scored approximate average of 0.16 seconds. Winner!
  • swap4() = scored approximate average of 0.73 seconds.

And for readability, I find swap3() is better than the other functions.

Note

  • swap2() and swap4() are always slower than the other ones because of the function call.
  • swap1() and swap3() both performance speed are very similar, but most of the time swap3() is slightly faster.
  • Warning: swap1() works only with numbers!
Wednesday, March 31, 2021
 
Sanguine
answered 10 Months ago
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