case insensitive "subtract" one text from another (php)

(Sorry! Revision regarding the $ character. Explaining via example as well)

I need to run a test on two string variable开发者_JAVA百科s:

$a, $b

If $a is contained in $b, I need to see if their "difference" ($b-$a) contains the $ character in it. If it does, then return the "difference", else in all other cases, the test should return FALSE

Also $a should only occur at the END of $b...

$b = "abcde" $a = "cde" should result in true (no $ detected)

$b = "zyw$abcde" $a = "cde" should result in false ($ detected)

$b = "cdeab" $a = "cde" should result in false (NOT at the end)

$b = "zxwq" $a = "cde" should result in false ($a doesnt exist in $b)

HTH!

---

• Use strpos to determine the position of $a in $b
• Use substr to get the parts from $b which do not contain $a
• Use strpos to check whether those parts contain $.

---

$ret = false;
if (strpos($b, $a) !== false) {
    $ret = (substr_count($b) > substr_count($a));
}

$ret is your answer

---

Edit: updated after question edit

This should work:

<?php

function string_func_thing($a, $b) {
    $count = 0;

    //get $b with $a removed
    $result = str_ireplace($a, '', $b, $count);   

    //if $a was not in $b
    if (!$count) {
        return false;
    }
    //if whatever is left contains $
    if (false !== strpos($result, '$')) {
        return false;
    }

    return true;
}


var_dump( string_func_thing('ter', 'computer$') ); //bool(false) 
var_dump( string_func_thing('ter', 'computer') ); //bool(true) 
var_dump( string_func_thing('hello', 'computer') ); //bool(true) 

---

$a = 'cde';
$regex = '/^[^$]*' . $a . '$/m';
if (preg_match($regex, $b)) {
    # Successful match
} else {
    # Match attempt failed
}