Delete everything except numbers and minus sign PHP preg_replace

Question

I have currently received

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

For example, entering GB -3. My current line gives me a value of 3. I want to be able to save the minus so that the value shows -3 instead of the current output of 3.

Answer 1

try the following:

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

regex breakdown:

• // on both sides is a regular expression separator - everything inside is a regular expression
• [] means that it is a character class. Change rules in a character class
• ^ Inner character class means not.
• \d abbreviated for [0-9], the only difference is that it can be used both inside and outside the character class
• - will match the minus sign
• + at the end - a quantifier, which means that it must match one or more characters.