删除除数字和减号之外的所有内容PHP preg_replace

Question

I've currently got

preg_replace('/[^0-9]/s', '', $myvariable); 

For example the input is GB -3. My current line is giving me the value 3. I want to be able to keep the minus so that the value shows -3 instead of the current output of 3.

Answer 1

try this :

preg_replace('/[^\d-]+/', '', $myvariable); 

breakdown of regex:

• // on both sides are regex delimiter - everything that is inside is regex
• [] means that this is character class. Rules change in character class
• ^ inside character class stands for "not".
• \d is short for [0-9], only difference is that it can be used both inside and outside of character class
• - will match minus sign
• + in the end is the quantifier, it means that this should match one or more characters