PHP remove commas from numeric strings

The easiest would be:

$var = intval(preg_replace('/[^\d.]/', '', $var));

or if you need float:

$var = floatval(preg_replace('/[^\d.]/', '', $var));

Do it the other way around:

$a = "1,435";
$b = str_replace( ',', '', $a );

if( is_numeric( $b ) ) {
    $a = $b;
}

Not tested, but probably something like if(preg_match("/^[0-9,]+$/", $a)) $a = str_replace(...)

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