Searching a array in PHP, performance improvements

Question

I've two A and B arrays, first one (A) is simple array where as the second one (B) is array of arrays. I want to find whether some element in A is equal to element in B. For doing this I'm currently doing nested loops which results in n^3 complexity. How can I improve upon this.

for ($i = 0; $i <= count($A); $i++) {
    if (isset($A[$i])) {
        foreach ($B as $items) {
            foreach ($items as $item) {
                if ($item['Column1'] == $A[$i]['Column1']) {
                    array_push(A, "result");
                    unset($A[$i]);
                    unset($items);
                    break;
                }
            }
        }
    }
}

Please, provide arrays examples and whanted result.

sectus
– sectus

2013-07-08 09:13:29 +00:00
Commented Jul 8, 2013 at 9:13 — sectus
– sectus, Commented Jul 8, 2013 at 9:13

Ziarno · Accepted Answer · 2013-07-08 09:16:36Z

2

array_walk_recursive($B, function($val) {
  if (in_array($val, $A)) echo "$val is in the \$A array!";
});

edited Jul 8, 2013 at 9:16

answered Jul 8, 2013 at 9:11

Ziarno

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1 Comment

Mangiucugna Over a year ago

a simple in_array cannot work, the $B array is multidimensional

dakshbhatt21 · Accepted Answer · 2013-07-08 09:40:47Z

1

Try this, array_seacrh() will remove your one foreach loop :

for ($i = 0; $i <= count($A); $i++) {
    if (isset($A[$i])) {
        foreach ($B as $items) {
            $t = array_search($A[$i]['Column1'], $items);
            array_push($A, "result");
            unset($A[$i]);
            unset($items[$t]);
        }
    }
}

answered Jul 8, 2013 at 9:40

dakshbhatt21

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Comments

lePunk · Accepted Answer · 2013-07-08 09:10:43Z

0

when creating your arrays you can create a $lookup_A and $lookup_B arrays, where the keys are the values from the original $A and $B

Then you can do a simple loop on $lookup_A and check for if (isset($lookup_B[$lookup_A_key]))

Also in your example if(isset($A[$i])) is always true i think

answered Jul 8, 2013 at 9:10

lePunk

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