regex - Extract floating point numbers from a string in PHP

Question

I would like to convert a string into floating numbers. For example

152.15 x 12.34 x 11mm

into

152.15, 12.34 and 11

and store in an array such that $dim[0]=152.15, $dim[1]=12.34, $dim[2]=11.

I would also need to handle things like

152.15x12.34x11 mm

152.15mmx12.34mm x 11mm

Thank you.

Answer 1

$str = '152.15 x 12.34 x 11mm';
preg_match_all('!d+(?:.d+)?!', $str, $matches);
$floats = array_map('floatval', $matches[0]);
print_r($floats);

The (?:...) regular expression construction is what's called a non-capturing group. What that means is that chunk isn't separately returned in part of the $mathces array. This isn't strictly necessary in this case but is a useful construction to know.

Note: calling floatval() on the elements isn't strictly necessary either as PHP will generally juggle the types correctly if you try and use them in an arithmetic operation or similar. It doesn't hurt though, particularly for only being a one liner.