如何应用正则表达式从动态字符串中获取数字

Question

I have a variable that can contain a few variations, it also contains a number which can be any number.

The variations:

($stuksprijs+9.075);
($stuksprijs-9.075);
($stuksprijs*9.075);

($m2+9.075);
($m2-9.075);
($m2*9.075);

($o+9.075);
($o-9.075);
($o*9.075);

These are the only variations except for the numbers in it, they can change. And I need that number.

So there can be:

($m2+5);

or

($o+8.25);

or

($stuksprijs*3);

How can I get the number from those variations? How can I get the 9.075 or 5 or 8.25 or 3 from my above examples with regular expression?

I am trying to fix this with PHP, my variable that contains the string is: $explodeberekening[1]

I read multiple regex tutorials and got it to work for a single string that never changes, but how can I write a regex to get the number from above variations?

Answer 1

As per my comment, which seems to have worked, you can try:

^\(\$(?:stuksprijs|m2|o)[+*-](\d+(?:\.\d+)?)\);$

The number is captured in the 1st capture group. See the online demo .

A quick breakdown:

• ^ - Start string anchor.
• \(\$ - Literally match "($".
• (?: - Open a non-capture group to list alternation:
  • stuksprijs|m2|o - Match one of these literal alternatives.
  • ) - Close non-capture group.
• [+*-] - Match one of the symbols from the character-class.
• ( - Open 1st capture group:
  • \d+ - 1+ digits.
  • (?:\.\d+)? - Extra optional non-capture group to match a literal dot and 1+ digits.
  • ) - Close 1st capture group.
• \); - Literally match ");".
• $ - End string anchor.