Php preg_match with wild card characters - php

Question

I have some zip code in an array which includes some wild card characters like this
$zip_codes = array( '12556', '765547', '234*', '987*' );
$target_zip = '2347890';
So to check whether the target zip is already present in the array. I am doing like this
foreach( $zip_codes as $zip ) {
if ( preg_match( "/{$target_zip}.*$/i", $zip ) ) {
echo 'matched';
break;
}
else {
echo 'not matched';
}
}
But its not matching the zip at all. Can someone tell me whats the issue here?

Answer 1

You need to turn your $zip values into valid regular expressions by converting * into .* (or perhaps \d*); then you can test them against $target_zip:
$zip_codes = array( '12556', '765547', '234*', '987*' );
$target_zip = '2347890';
foreach( $zip_codes as $zip ) {
echo $zip;
if (preg_match('/' . str_replace('*', '.*', $zip) . '/', $target_zip)) {
echo ' matched'. PHP_EOL;
break;
}
else {
echo ' not matched' . PHP_EOL;
}
}
Output:
12556 not matched
765547 not matched
234* matched
Demo on 3v4l.org
You haven't indicated whether you want the value in $zip_codes to match the entire $target_zip value or just part of it. The code above will work for just part (i.e. 234 will match 12345); if you don't want that, change the regex construction to:
if (preg_match('/^' . str_replace('*', '.*', $zip) . '$/', $target_zip)) {
The anchors will ensure that $zip matches the entirety of $target_zip.

Answer 2

One of the problems is that using 234* in a regex will match any number of 4's.
The other problem is that you match to the end (using $) but not the start, so 789 (with the .* appended) will also match (as it's in the middle). In this code, I use ^{$zip}$, with * replaced with .* to match any trailing characters...
$zip_codes = array( '12556', '765547', '789', '234', '234*', '987*' );
$target_zip = '2347890';
foreach( $zip_codes as $zip ) {
$zip = str_replace("*", ".*", $zip);
if ( preg_match( "/^{$zip}$/i", $target_zip ) ) {
echo $zip.' matched'.PHP_EOL;
break;
}
else {
echo $zip.' not matched'.PHP_EOL;
}
}

Answer 3

You don't need regex here.
You can look for * and based on that look for an exact on the number of characters -1.
$zip_codes = array( '12556', '765547', '234*', '987*' );
$target_zip = '2347890';
foreach($zip_codes as $zip){
if(strpos($zip, "*") !== false){
//if "234* -1 = "234" == substr("2347890",0,3)
if(substr($zip, 0, -1) == substr($target_zip, 0, strlen($zip)-1)){
echo "wildcard match";
}
}else{
if($zip == $target_zip){
echo "excat match";
}
}
}
https://3v4l.org/hIGER

Answer 4

The issue is that in the loop, the pattern is always the same:
if ( preg_match( "/2347890.*$/i", $zip ) ) {
I think you meant to use the value of $zip as part of the pattern, which causes the issue repeating the last digit 0+ times in:
if ( preg_match( "/234*.*$/i", $zip ) ) {
^^
As an alternative, you could also extract the digits from $zip_codes using a capturing group and match optional following *
^(\d+)\**$
Regex demo
Then use strpos to check if the target_zip start with the extracted digits.
$zip_codes = array( '12556', '765547', '234*', '987*', '237' );
$target_zip = '2347890';
foreach($zip_codes as $zip ) {
$digitsOnly = preg_replace("~^(\d+)\**$~", "$1", $zip);
if (strpos($target_zip, $digitsOnly) === 0) {
echo "$zip matched $target_zip" . PHP_EOL;
break;
}
else {
echo "$zip not matched $target_zip" . PHP_EOL;
}
}
Output
12556 not matched 2347890
765547 not matched 2347890
234* matched 2347890
Php demo