Using regex to fix phone numbers in a CSV with PHP
- by Hurpe
My new phone does not recognize a phone number unless it's area code matches the incoming call. Since I live in Idaho where an area code is not needed for in-state calls, many of my contacts were saved without an area code. Since I have thousands of contacts stored in my phone, it would not be practical to manually update them. I decided to write the following PHP script to handle the problem. It seems to work well, except that I'm finding duplicate area codes at the beginning of random contacts.
<?php
//the script can take a while to complete
set_time_limit(200);
function validate_area_code($number) {
//digits are taken one by one out of $number, and insert in to $numString
$numString = "";
for ($i = 0; $i < strlen($number); $i++) {
$curr = substr($number,$i,1);
//only copy from $number to $numString when the character is numeric
if (is_numeric($curr)) {
$numString = $numString . $curr;
}
}
//add area code "208" to the beginning of any phone number of length 7
if (strlen($numString) == 7) {
return "208" . $numString;
//remove country code (none of the contacts are outside the U.S.)
} else if (strlen($numString) == 11) {
return preg_replace("/^1/","",$numString);
} else {
return $numString;
}
}
//matches any phone number in the csv
$pattern = "/((1? ?\(?[2-9]\d\d\)? *)? ?\d\d\d-?\d\d\d\d)/";
$csv = file_get_contents("contacts2.CSV");
preg_match_all($pattern,$csv,$matches);
foreach ($matches[0] as $key1 => $value) {
/*create a pattern that matches the specific phone number by adding slashes before possible special characters*/
$pattern = preg_replace("/\(|\)|\-/","\\\\$0",$value);
//create the replacement phone number
$replacement = validate_area_code($value);
//add delimeters
$pattern = "/" . $pattern . "/";
$csv = preg_replace($pattern,$replacement,$csv);
}
echo $csv;
?>
Is there a better approach to modifying the csv? Also, is there a way to minimize the number of passes over the csv? In the script above, preg_replace is called thousands of times on a very large String.
