Why does while(0) not execute the code? [closed] - php

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<?php
$efFect=0;
$find='is';
$find_len=strlen($find);
$string22 ='this is space is function';
while ($str_position =strpos($string22,$find,$effect)){
echo $find.'the postion in '. $str_position.'<br>';
$efFect = $str_position + $find_len ;
}
?>

Answer 1

0 is a falsy value. You should make your check more reliable by checking if strpos actually returns false.
<?php
$effect=0; // not $efFect as variables names are case sensitive in PHP
$find='is';
$find_len=strlen($find);
$string22 ='this is space is function';
while (($str_position = strpos($string22, $find, $effect)) !== False){
echo $find.'the postion in '. $str_position.'<br>';
$effect = $str_position + $find_len ;
}
?>
From the documentation:
Returns the position of where the needle exists relative to the beginning of the haystack string (independent of offset). Also note that string positions start at 0, and not 1.
Returns FALSE if the needle was not found.
Someone mentioned that your code creates an infinite loop but this is not the case. strpos accepts an offset as the third parameter which you have correctly used. On each iteration the offset is incremented such that the new search will begin at the position where the last found result string ends, hence avoiding the infinite loop.