Question

How can I use str_replace method for replacing a specified portion(between two substrings).
For example,

string1="www.example.com?test=abc&var=55";
string2="www.example.com?test=xyz&var=55";

I want to replace the string between '?------&' in the url with ?res=pqrs&. Are there any other methods available?

Answer 1

Dirty version:

$start = strpos($string1, '?');
$end = strpos($string1, '&');

echo substr($string1, 0, $start+1) . '--replace--' . substr($string1, $end);

Better:

preg_replace('/\?[^&]+&/', '?--replace--&', $string1);

Depending on whether you want to keep the ? and &, the regex can be mofidied, but it would be quicker to repeat them in the replaced string.