Validate numbers

[Nodral]

Hi All

 

I'm a bit of a newbie to regex and am struggling with what seems like the most basic preg_replace.

 

I need to validate numbers and remove anything non-numeric from a string.

 

ie 4.5volts would become 4.5

-67 degrees would be -67

 

I have this

 

preg_replace('/[^.-0-9]/', '', $aValue['value']);

 

however there can only be one minus and it must be at the start, and there can only be one decimal point.

 

Any help is much appreciated.

[Nodral]

I now have

preg_match('[-\+]?\b[0-9]+(\.[0-9]+)?\b', $value['value'], $match);

 

However I am getting error

preg_match() [function.preg-match]: Unknown modifier '?' in.....

 

Come on guys, I really need this one!! lol

 

[scootstah]

Can't you just use typecasting?

 

<?php

$i = '-65.55asdfasdfasdf';

echo (int) $i; // -65

echo (float) $i; // -65.55

[Jessica]

For more: http://us2.php.net/manual/en/language.types.type-juggling.php

[Christian F.]

You really should be using typecasting for this, as mentioned above.

 

That said, the problems you had with your second RegExp are as follows:

1. [*]Missing delimiters, which causes the RegExp engine to assume that the opening [ is a delimiter. Thus the error.

[*]Use of word boundaries. Especially in between the notation sign and the value.

You don't need the word boundaries at all, as the + is a greedy modifier and you've asked it to match digits only. Also, you could have used \\d instead of [0-9] to tell the RegExp engine that you wanted a digit.