Using preg_replace pattern to clean a string

Question

I want to use php preg_replace to remove (note that i want them removed, so i dont want to use htmlentities)

I want to allow the charecters a-z, A-Z, 0-9, and the special chars "@_." only

Answer 1

Pretty straight-forward:

$string = preg_replace('/[^a-zA-Z0-9@.]+/', '', $string);

In simple English: Replace one or more occurrences of anything that's not an alphabet, number or the symbol @, ., with nothing.

Autopsy:

• / - starting delimiter
• [^a-zA-Z0-9@.] - a character class
  • ^ - used to negate the character class
  • a-zA-Z0-9 - alphabets or numbers
  • @ - literal character @
  • . - literal character .
• + - match the previous quantity one or more times
• / ending delimiter