Need a reg-ex to match a length in mm

Question

Im using PHP preg_match() method. I am having trouble with a regular expression to match a mm length. The numeerical length can be a float...here are some exmaples of the data I am working on;

1.0mm

25.5mm

3mm

3 mm

3.3 mm

So bacially any integer or float proceeded by "mm" with or without whitespace between.

Thanks!

Answer 1

Try '/(\d+(?:\.\d+)?)\s*mm/' and you'll have the number in $1.

Explanation:

• ( begin capturing group
• \d+ one or more digits
• (?: begin non-capturing group
• \. litteral dot
• \d+ one or more digits
• ) end non-capturing group
• ? the non-capturing group ("." + digits) may not be present
• ) end capturing group
• \s* zero or more whitespaces (or tabs, etc.)
• mm literal "mm"

Answer 2

Do you need a regex for this? if you use something like floatval on "123.122mm" it should give you 123.122 numeric and ignore the text.