Loop through each character in a string in PHP

<?php


$str = "String to loop through"


$strlen = strlen( $str );


for( $i = 0; $i <= $strlen; $i++ ) {


    $char = substr( $str, $i, 1 );


    // $char contains the current character, so do your processing here


}


?>








Once I had the loop set up I simply added an is_ numeric() check and inserted a break command the first time the check returned false – here is my use case:





<?php


$str = "123?param=value"


$strlen = strlen( $str );


$id = "";


for( $i = 0; $i <= $strlen; $i++ ) {


    $char = substr( $str, $i, 1 );


    if( ! is_numeric( $char ) ) { break; }


    $id .= $char;


}


// $id now contains the ID I need, in this case: 123


?>