Function to return only alpha-numeric characters from string

Question

I m looking for a php function that will take an input string and return a sanitized version of it by stripping away all special characters leaving only alpha-numeric   I need a second function that does the same but only returns alphabetic characters A-Z   Any help much appreciated

User · Answer

Rather than preg replace  you could always use PHP s filter functions using the filter var   function with FILTER SANITIZE STRING

User · Answer

Warning  Note that English is not restricted to just A-Z   Try this to remove everything except a-z  A-Z and 0-9    result   preg replace     a-zA-Z0-9           s     If your definition of alphanumeric includes letters in foreign languages and obsolete scripts then you will need to use the Unicode character classes   Try this to leave only A-Z    result   preg replace     A-Z           s     The reason for the warning is that words like r  sum   contains the letter    that won t be matched by this  If you want to match a specific list of letters adjust the regular expression to include those letters  If you want to match all letters  use the appropriate character classes as mentioned in the comments

[php] Function to return only alpha-numeric characters from string?

Examples related to php

Examples related to regex