PHP check if array contains start of string

Question

How can I check if the start of a given value matches an entry in a predefined list of values?

$model_no1 = "KK71458";
$model_no2 = "IX41";

$models = array("KK61", "KK71", "KK81", "IX", "IJ");

In the above sample code, both values should return a valid match.

Whats your input (x number of strings, one string)? How should your output look? — Frederik Wordenskjold
– Frederik Wordenskjold, Commented Feb 12, 2014 at 9:57
How large arrays and strings do you want to be able to process? Naive solutions to this would be very inefficient for large arrays/strings. — Dogbert
– Dogbert, Commented Feb 12, 2014 at 9:57
Just one string. The array will contain no more than a hundred entries similar to the above. — MAX POWER
– MAX POWER, Commented Feb 12, 2014 at 9:58

HarryIsBack · Accepted Answer · 2014-02-12 10:15:44Z

2

Try this:

$model_no1 = "KK71458";
    $models = array("KK61", "KK71", "KK81", "IX", "IJ");
    foreach($models as $key=> $mod){
        if($mod == substr($model_no1,0,strlen($mod))){ 
            echo "key: ".$key.' with value: '.$mod;
        }
    }

answered Feb 12, 2014 at 10:15

HarryIsBack

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Comments

Alexander Yancharuk · Accepted Answer · 2014-02-12 10:50:40Z

I would recommend use strpos() function rather than combination of substr() and strlen() in your case:

$model_no1 = 'KK71458';
$model_no2 = 'IX41';

$models = array('KK61', 'KK71', 'KK81', 'IX', 'IJ');
$result1 = check_model($model_no1, $models);
$result2 = check_model($model_no2, $models);

function check_model($model_no, array $models) {
    foreach ($models as $needle) {
        if (0 === strpos($model_no, $needle))
            return true;
    }

    return false;
}

I wrote the simple test for checking string comparison performance by strpos(), strstr() and substr()+strlen(). Here is results:

Test name       Repeats         Result          Performance     
strpos          10000           0.167221 sec    +0.00%
strstr          10000           0.169299 sec    -1.24%
substr+strlen   10000           0.207363 sec    -24.01%

As you see strpos() has best performance results.

silly · Accepted Answer · 2014-02-12 10:12:44Z

0

$models = array("KK61", "KK71", "KK81", "IX", "IJ");

$g = function($search) use ($models) {
    return array_filter($models, function($string) use($search) {
        return substr($search, 0, strlen($string)) == $string;
    });
};

print_r($g->__invoke('KK71458'));
print_r($g->__invoke('IX41'));
print_r($g->__invoke('SPONGEBOB'));

answered Feb 12, 2014 at 10:12

silly

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Comments

Popeye · Accepted Answer · 2022-01-14 14:43:34Z

0

HarryIsBack has reversed $mod and $model_no1.

Correct like this :

$model_no1 = "KK71458";
    $models = array("KK61", "KK71", "KK81", "IX", "IJ");
    foreach($models as $key=> $mod){
        if($model_no1 == substr($mod,0,strlen($model_no1))){ 
            echo "key: ".$key.' with value: '.$mod;
        }
    }

answered Jan 14, 2022 at 14:43

Popeye

1

1 Comment

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