Regular expression to only allow whole numbers and commas in a string

Question

Does anyone know what the preg_replace would be for a string to only allow whole numbers and commas? I want to strip all whitespace, letters, symbols, etc, so all that is le

Answer 1

Here's the answer to your question:

//drop all characters except digits and commas
    preg_match_all('/[\\d,]/', $subject, $result, PREG_PATTERN_ORDER);
    $result = implode('', $result[0]);

//strip the empty or trailing commas
    if( preg_match('/^,*(\\d.*?\\d),*$/', $result, $regs) ){
        $result = $regs[1];
    }

But you might want to use this function instead?

Sounds like a function I once wrote. See: https://github.com/homer6/altumo/blob/master/source/php/Validation/Arrays.php

/**
* Ensures that the input is an array or a CSV string representing an array.
* If it's a CSV string, it converts it into an array with the elements split 
* at the comma delimeter.  This method removes empty values. 
* 
* Each value must be a postitive integer.  Throws and exception if they aren't
* (doesn't throw on empty value, just removes it).  This method will santize
* the values; so, if they're a string "2", they'll be converted to int 2.
* 
* 
* Eg.
*     sanitizeCsvArrayPostitiveInteger( '1,2,,,,3' );   //returns array( 1, 2, 3 );
*     sanitizeCsvArrayPostitiveInteger( array( 1, 2, 3 ) );   //returns array( 1, 2, 3 );
*     sanitizeCsvArrayPostitiveInteger( array( 1, "hello", 3 ) );   //throws Exception
*     sanitizeCsvArrayPostitiveInteger( '1,2,,"hello",,3' );   //throws Exception
* 
* @param mixed $input
* @throws Exception //if $input is not null, a string or an array
* @throws Exception //if $input contains elements that are not integers (or castable as integers)
* @return array
*/
static public function sanitizeCsvArrayPostitiveInteger( $input );