[php] Remove non-numeric characters (except periods and commas) from a string

If I have the following values:

 $var1 = AR3,373.31

 $var2 = 12.322,11T

How can I create a new variable and set it to a copy of the data that has any non-numeric characters removed, with the exception of commas and periods? The values above would return the following results:

 $var1_copy = 3,373.31

 $var2_copy = 12.322,11

You could use filter_var to remove all illegal characters except digits, dot and the comma.

• The FILTER_SANITIZE_NUMBER_FLOAT filter is used to remove all non-numeric character from the string.
• FILTER_FLAG_ALLOW_FRACTION is allowing fraction separator " . "
• The purpose of FILTER_FLAG_ALLOW_THOUSAND to get comma from the string.

Code

$var1 = '12.322,11T';

echo filter_var($var1, FILTER_SANITIZE_NUMBER_FLOAT, FILTER_FLAG_ALLOW_FRACTION | FILTER_FLAG_ALLOW_THOUSAND);

Output

12.322,11

To read more about filter_var() and Sanitize filters

I'm surprised there's been no mention of filter_var here for this being such an old question...

PHP has a built in method of doing this using sanitization filters. Specifically, the one to use in this situation is FILTER_SANITIZE_NUMBER_FLOAT with the FILTER_FLAG_ALLOW_FRACTION | FILTER_FLAG_ALLOW_THOUSAND flags. Like so:

$numeric_filtered = filter_var("AR3,373.31", FILTER_SANITIZE_NUMBER_FLOAT,
    FILTER_FLAG_ALLOW_FRACTION | FILTER_FLAG_ALLOW_THOUSAND);
echo $numeric_filtered; // Will print "3,373.31"

It might also be worthwhile to note that because it's built-in to PHP, it's slightly faster than using regex with PHP's current libraries (albeit literally in nanoseconds).

Simplest way to truly remove all non-numeric characters:

echo preg_replace('/\D/', '', $string);

\D represents "any character that is not a decimal digit"

http://php.net/manual/en/regexp.reference.escape.php

If letters are always in the beginning or at the end, you can simply just use trim...no regex needed

$string = trim($string, "a..zA..Z"); // this also take care of lowercase

"AR3,373.31" --> "3,373.31"
"12.322,11T" --> "12.322,11"
"12.322,11"  --> "12.322,11"