How to remove single character words from string with preg_replace

Question

Given the following input -

"I went to 1 ' and didn't see p"

, what is the regular expression for PHP's preg_replace function to remove all single characters (and left over spaces) so that the output would be -

"went to and didn't see".

I have been searching for a solution to this but cannot find one. Similar examples haven't included explanations of the regular expression so i haven't been able to adapt them to my problem. So please, if you know how to do this, provide the regular expression but also break it down so that I can understand how it works.

Cheers

Answer 1

Try this:

$output = trim(preg_replace("/(^|\s+)(\S(\s+|$))+/", " ", $input));

• (^|\s+) means "beginning of string or space(s)"
• (\s+|$) means "end of string of space(s)"
• \S is single non-space character