Allow only dots and numbers on variable?

[invision2]

Hi,

What's a solid regular expression for allowing just integers and dots in a variable?


Could do with an online reference for RegExp actually. Any kind folk know of such?



Many thanks

[AnthonySterling]

<?php
if(1 !== preg_match('~[^0-9.]~', '1234567890.'))
{
    #valid
}
?>

I quite like RegExr at the moment, a nice live flash based tester by RegExp guru Grant Skinner.

[invision2]

Brilliant stuff Anthony, thanks again.

Pops into wardrobe, picks out stupid hat, then says...In this case would '1' be my variable name?

[AnthonySterling]

Nope, `1234567890.` would be.

[invision2]

Aaaaah of course. And '1' just represents TRUE ?

Too late in the afternoon. Thanks once more Anthony.

[AnthonySterling]

No worries mate.

preg_match can return 0, 1 or false. If it finds a match it will return 1, our pattern searches for anything that is NOT numeric or a period. If it finds a match (therefore returning 1) we know the variable contains an invalid char.

Make sense?

From the manual:

preg_match() returns the number of times pattern matches. That will be either 0 times (no match) or 1 time because preg_match() will stop searching after the first match. preg_match_all() on the contrary will continue until it reaches the end of subject . preg_match() returns FALSE if an error occurred.