php array_multisort使用数组名称作为参数

Question

Sorry if this is duplicate, I have tried to look at previous posts, but maybe my limited understanding of php gets in the way.

This works to sort arrays 1 and 3 by array 2:

<?php

$ar[1] = array("game","scissors","rock","paper");
$ar[2] = array("D", "B", "A", "C");
$ar[3] =array("four","two","one","three");

array_multisort($ar[2],$ar[1],$ar[3]);

for ($j=0;$j<=3;$j++) {

    for ($i=1;$i<=3;$i++) {
  echo $ar[$i][$j]." ";
}
echo "\n";
}

?>

output:

rock A one
scissors B two
paper C three
game D four

Fine. But I want the list of arrays used as argument for array_multisort() to be specified by user input, so it can't be literal. Instead, I would like the program to decide the order of arrays in the list based on the user input and then name the resulting array of arrays $supar (superarray). But when using $supar as argument for array_multisort() , no sorting is carried out.

<?php

$ar[1] = array("game","scissors","rock","paper");
$ar[2] = array("D", "B", "A", "C");
$ar[3] =array("four","two","one","three");


$supar = array($ar[2],$ar[1],$ar[3]);
array_multisort($supar);

for ($j=0;$j<=3;$j++) {

    for ($i=1;$i<=3;$i++) {
  echo $ar[$i][$j]." ";
}
echo "\n";
}

?>

Output:

game D four
scissors B two
rock A one
paper C three

How should I do to make array_multisort() sort the arrays in $supar by a specified $ar array?

Thank you for your patience.

Answer 1

You can't do that with just the PHP function. array_multisort() takes the different arrays separately as arguments and you can't just pass a different thing with the intended arguments inside.

What you could do is writing your own function to do that for you. Something like:

function my_multisort($supar) {
    array_multisort($supar[2], $supar[1], $supar[3]);
}

$supar = array(
    array("game","scissors","rock","paper"),
    array("D", "B", "A", "C"),
    array("four","two","one","three")
);

my_multisort($supar);

EDIT

As @axiac correctly pointed out, this is basically a weird specific way of reinventing call_user_func_array() . You can simply build your array of arguments $supar as you need and then do

call_user_func_array('array_multisort', $supar);

Answer 2

You can call array_multisort() (or any other function) without specifying its arguments explicitly if you have the arguments in an array by using call_user_func_array() .

array_multisort() gets its arguments by reference (in order to be able to modify them). You have to consider this when you build the array you use as argument to call_user_func_array() and put references in this array:

// Input arrays
$ar[1] = array("game", "scissors", "rock", "paper");
$ar[2] = array("D", "B", "A", "C");
$ar[3] = array("four", "two", "one", "three");

// Build the list of arguments for array_multisort()
// Use references to the arrays you want it to sort
$supar = array(&$ar[2], &$ar[1], &$ar[3]);

// Call array_multisort() indirectly
// This is the same as array_multisort($ar[2], $ar[1], $ar[3]);
call_user_func_array('array_multisort', $supar);

Check it in action: https://3v4l.org/ptiog