Most efficient way to check if array element exists in string

Question

I've been looking for a way to check if any of an array of values exists in a string, but it seems that PHP has no native way of doing this, so I've come up with the below.

My question - is there a better way of doing this, as this seems pretty inefficient? Thanks.

$match_found = false;
$referer = wp_get_referer();
$valid_referers = array(
    'dd-options',
    'dd-options-footer',
    'dd-options-offices'
);

/** Loop through all referers looking for a match */
foreach($valid_referers as $string) :

    $referer_valid = strstr($referer, $string);
    if($referer_valid !== false) :
        $match_found = true;
        continue;
    endif;

endforeach;

/** If there were no matches, exit the function */
if(!$match_found) :
    return false;
endif;

the continue; does not make much sense, as there is no more code inside the loop which could be skipped. If you only want to know if there is at least one match, use break; instead. This way the loop will stop at the first match. — Yoshi
– Yoshi, Commented Jan 9, 2013 at 12:46
Inside your foreach - you want to break once you have found the first matching referer (and not to continue). Edit: beaten by Yoshi :) — Sim
– Sim, Commented Jan 9, 2013 at 12:48
@Yoshi - Good spot on that one thanks - an erro in my part in not changing to break; after an earlier attempt! — David Gard
– David Gard, Commented Jan 9, 2013 at 15:54

hsz · Accepted Answer · 2013-01-09 12:46:55Z

3

Try with following function:

function contains($input, array $referers)
{
    foreach($referers as $referer) {
        if (stripos($input,$referer) !== false) {
            return true;
        }
    }
    return false;
}

if ( contains($referer, $valid_referers) ) {
  // contains
}

answered Jan 9, 2013 at 12:46

hsz

153k63 gold badges269 silver badges320 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

David Gard Over a year ago

Think I'll go for something like that. Thanks for the suggestion.

shadyyx · Accepted Answer · 2013-01-09 12:48:15Z

0

What about this:

$exists = true;
array_walk($my_array, function($item, $key) {
    $exists &= (strpos($my_string, $item) !== FALSE);
});
var_dump($exists);

This will check if any of the array values exists in the string. If only one is missing, You are given a false response. Should You need to find out which one are not present in the string, try this:

$exists = true;
$not_present = array();
array_walk($my_array, function($item, $key) {
    if(strpos($my_string, $item) === FALSE) {
        $not_present[] = $item;
        $exists &= false;
    } else {
        $exists &= true;
    }
});
var_dump($exists);
var_dump($not_present);

answered Jan 9, 2013 at 12:48

shadyyx

16.1k7 gold badges62 silver badges98 bronze badges

Comments

Khez · Accepted Answer · 2013-01-09 12:53:26Z

0

First of, alternate syntax is nice to use, but historically it's used in template files. Since it's structure is easily readable while coupling/decouping the PHP interpreter to interpolate HTML data.

Second, it's generally wise if all your code does is to check something, to immediately return if that condition is met:

$match_found = false;
$referer = wp_get_referer();
$valid_referers = array(
    'dd-options',
    'dd-options-footer',
    'dd-options-offices'
);

/** Loop through all referers looking for a match */
foreach($valid_referers as $string) :

    $referer_valid = strstr($referer, $string);
    if($referer_valid !== false) :
        $match_found = true;
        break; // break here. You already know other values will not change the outcome
    endif;

endforeach;

/** If there were no matches, exit the function */
if(!$match_found) :
    return false;
endif;

// if you don't do anything after this return, it's identical to doing return $match_found

Now as specified by some of the other posts in this thread. PHP has a number of functions that can help. Here's a couple more:

in_array($referer, $valid_referers);// returns true/false on match

$valid_referers = array(
    'dd-options' => true,
    'dd-options-footer' => true,
    'dd-options-offices' => true
);// remapped to a dictionary instead of a standard array
isset($valid_referers[$referer]);// returns true/false on match

Ask if you have any questions.

answered Jan 9, 2013 at 12:53

Khez

10.3k2 gold badges35 silver badges53 bronze badges

2 Comments

David Gard Over a year ago

Thaks for the suggestion. Am I correct in thinking thought that in_array() would only check that $referrer exactly met one of the values in $valid_referers? If so, that won't work as $referer is a HTTP referer (so HTTP://www.somting.com/page?referrer=dd-options&page_id=65, for example).

Khez Over a year ago

in_array, is a strict comparison function. So yes, it's needle must be exactly equal to the value of an item from array. Also I'm uncertain what wp_get_referer does. I'm guessing it's a wordpress function but that's about it. You can get it in your example with $referer=$_GET['referrer']. Are these the only 3 valid options ?

Collectives™ on Stack Overflow

Most efficient way to check if array element exists in string

3 Answers 3

1 Comment

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related