Question

what to do if I want to replace only the first occurrence of a word in a string.
eg: I want to change the first occurrence of heelo in a string with kiran.

input string == **"hello world i am a noob hello to all"**
output string == **"kiran world i am a noob hello to all"**

the str_replace is not working.

Answer 1

You could use preg_replace. The 4th arugment of this functions allows you to set how many times a replacement should occur.

$output = preg_replace( "/$find/", $replace, $input, 1 );

If you don’t want regular expression meta-characters to be interpretted in the search string, use:

$output = preg_replace( "/\\Q$find\\E/", $replace, $input, 1 );