PHP regular expression - filter number only

Question

I know this might sound as really dummy question, but I'm trying to ensure that the provided string is of a number / decimal format to use it later on with PHP's number_format() function.

How would I do it - say someone is typing 15:00 into the text field - what regular expression and php function should I use to remove the colon from it and make it only return the valid characters.

preg_match() returns array - so I can't pass the result to number_format() unless I implode() it or something like this.

Your help would be very much appreciated.

Answer 1

Using is_numeric or intval is likely the best way to validate a number here, but to answer your question you could try using preg_replace instead. This example removes all non-numeric characters:

$output = preg_replace( '/[^0-9]/', '', $string ); 

Answer 2

To remove anything that is not a number:

$output = preg_replace('/[^0-9]/', '', $input); 

Explanation:

• [0-9] matches any number between 0 and 9 inclusively.
• ^ negates a [] pattern.
• So, [^0-9] matches anything that is not a number, and since we're using preg_replace, they will be replaced by nothing '' (second argument of preg_replace).