Remove first instance of a term in string - case insensitive - php

Question

I have:
$string = 'Hello x World hello';
And I want to remove the first instance of a term that is case insensitive.
For example, I have:
$term = 'hello';
And I want to match it with $string, so we end up with:
$string = ' x World hello';
What I've done so far
I am nearly there! I can replace the first instance of a term with:
function str_replace_once($str_pattern, $str_replacement, $string){
if (strpos($string, $str_pattern) !== false){
$occurrence = strpos($string, $str_pattern);
return substr_replace($string, $str_replacement, strpos($string, $str_pattern), strlen($str_pattern));
}
return $string;
}
But it is not case insensitive, see ideone. How can I make it case insensitive?

Answer 1

In your example code, just replace strpos with stripos... (with a few minor tweaks)...
function str_replace_once($str_pattern, $str_replacement, $string){
$pos = stripos($string, $str_pattern);
if ($pos !== false){
return substr_replace($string, $str_replacement, $pos, strlen($str_pattern));
}
return $string;
}

Answer 2

I wish str_ireplace had a limit, it would be better. But preg_replace has a limit. Use the i modifier for case-insensitive:
$string = preg_replace("/$term/i", "", $string, 1);
Also note that there is a stripos which is case-insensitive strpos which you can use in your existing code.

Answer 3

Use stripos(case-insensitive) and substr
function str_replace_first($str, $search, $replace)
{
$index = stripos($str, $search);
return $index === false ? $str : substr($str, 0, $index) . $replace . substr($str, $index + strlen($search));
}
Usage:
$string = 'Hello x World hello';
echo str_replace_first($string,'Hello', '');