Regex help

[inverse.chi]

Hi,

I want to be able to write a regular expression that matches whole and decimal numbers as well as negatives, however there's a few problems with what i have so far and that is that it matches -0 when i want it to not match that. how would i resolve this? also it allows numbers like 038.48 to be added

^(-|)(\d+[.]\d+|0|\d+)$

thanks in advance

[ScallioXTX]

^-?\d*\.?\d*$

[inverse.chi]

Hi thank you for replying, however that still matches -0 and numbers such as 029 038.9 and 1.0

[ScallioXTX]

Okay,

Try this: ^-?(?!0)[0-9]*\.?\d*$


The (?!) is called the "Nagative Lookahead", it says that the character defined here may not be the next character in the string (so, the 0 in this case). It prevents numbers like -0 or 0123

Edit:


This still matches 1.0, but I'm not sure how to avoid this. Just asserting the first character after the decimal cannot be a 0 doesn't help, because that would also exclude 1.01
Maybe catch this in your scripting language

if ((int)$num == $num) $num = (int)$num;

to cast it to an integer

[logic_earth]

^([-+]?[1-9]\d*(?:\.(?:[1-9]|\d+[1-9]))?)$

Could probably improve on it by using look arounds.