Initializing Multiple PHP Variables Simultaneously

$first = $second = $third = $fourth = 0;

While it is feasible to initialize multiple variables using a comma operator within a for-loop, as follows:

<?php
for ($a=0,$b=0,$c=0,$d=0;;) {
    break;
}
var_dump($a,$b,$c,$d);

(See demo here)

the list construct provides a more efficient way to perform multiple variable assignment, as depicted in the following example:

<?php

list( $first, $second, $third, $fourth ) = array( 0, 0, 0, 0 );
var_dump($first, $second, $third, $fourth );

See demo here

One may wish to reconsider avoiding the usage of arrays to achieve multiple initialized variables. With PHP7.1+ one may write simpler, robust code if one utilizes array destructuring available with short array syntax, as follows:

<?php

[$first, $second, $third, $fourth ] = [0, 0, 0, 0];
var_dump($first, $second, $third, $fourth );

See demo here.

If one needs to be certain that the variables being initialized were not previously set, see this related discussion, particularly this response.

If you want to initialize multiple array variables then use

# Initialize multiple array variables with Empty values
$array_1 = $array_2 = $array_3 = array();

# Initialize multiple array variables with Some values in it
list( $array_1, $array_2, $array_3) = array('one','two','three');

# Print value of array variables
var_dump($array_1,$array_2,$array_3);

Output:
*******
string 'one' (length=3)
string 'two' (length=3)
string 'three' (length=5)

If you want to initialize multiple regular variables then use

# Initialize multiple regular variables with values
$a = $b = $c = 'Hello PHP';
echo $a.'<br>',$b.'<br>', $c.'<br>';

Output:
*******
Hello PHP
Hello PHP
Hello PHP