Search array for multiple strings?

Question

I’m searching for IF a string matching the email domains is present in a recordset.

$outsideService is our array of needles to look for:

$outsideService = array('guest.booking.com','vrbo.com'); // Add outside services to screen for not having emails in DB

My recordset array is $OS as created below:

$OS = ($Departing->Results); // Gather recordset  array

From that array I create a new array with just the email col:

$DepartingOS = array_column($OS, 'email'); // [index, value]

Result (haystack):

 Array
 (
     [0] => [email protected]
     [1] => [email protected]
     [2] => 0
 )

So now I need to compare to see IF the needle is in the haystack :

 if(preg_match($outsideService, $DepartingOS)) {
    echo ’True’;
}

This did not work. I believe the problem is preg_match does not work with an array as the haystack? Meaning I would need to loop the array looking for the needle each time.

But I also tried this method where the needles are set manually and still no luck.

if(preg_match('(guest.booking.com|vrbo.com)', $DepartingOS)===1) {
echo 'True';
}

Am I using preg_match wrong? How would I search the recordset array for the needles?

Nick · Accepted Answer · 2020-01-07 21:00:42Z

1

What you really need to do is iterate each of your arrays, checking whether any value of $outsideService is located within a value inside $DepartingOS. You can do this with a nested array_reduce, using strpos to check for a match:

$outsideService = array('guest.booking.com','vrbo.com');
$DepartingOS = array('[email protected]', '[email protected]', '0');

if (array_reduce($outsideService, function ($c, $OS) use ($DepartingOS) {
    return $c || array_reduce($DepartingOS, function ($c, $DOS) use ($OS) {
        return $c || (strpos($DOS, $OS) !== false);
    }, false);
}, false)) {
    echo "True";
}

Output:

True

This can also be written more simply as a nested foreach loop:

$found = false;
foreach ($outsideService as $OS) {
    foreach ($DepartingOS as $DOS) {
        if (strpos($DOS, $OS) !== false) {
            $found = true;
            break 2;
        }
    }
}
if ($found) {
    echo "True";
}

Demo on 3v4l.org

edited Jan 7, 2020 at 21:00

answered Jan 7, 2020 at 1:57

Nick

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2 Comments

Burndog Over a year ago

Yes, this works though it's hard for me to understand (learn). What does the $c reference (abbrevieation)?

Nick Over a year ago

@Burndog I apologise. Sometimes I get carried away with PHPs array functions. Anyway to answer your question, $c is an accumulator and it just tracks the current state of whether we have found a match or not; it is the value ultimately returned by array_reduce. But I have edited my answer with a simple nested foreach loop which is probably better code to use anyway.

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