find all array elements in another array

Question

I have two arrays-

$ar = array("a","b","c");
$xy = array("a","b","c","d","e");

I have to find out each element in $ar in $xy. If all elements are in $xy then it should return true.

I used in_array() but it returns true though one element is found.

Any help is appreciated. Thanks.

possible duplicate of [PHP - Check if two array are equal](http://stackoverflow.com/questions/5678959/php-check-if-two-array-are-equal) — Gordon, Jul 22 '11 at 09:15
@gordon: That dupe checks for equality which won't work for this question. However a good related one. — hakre, Jul 22 '11 at 09:32
@hakre there is multiple answers to that question. It contains all the OP needs (and could have found in the manual easily if he had bothered to search). A dupe isnt a dupe just for the accepted answer. — Gordon, Jul 22 '11 at 09:34
@Gordon: Sure, was just saying. But the premise of the question differs. Find all of one set in another set or compare two sets for equality. — hakre, Jul 22 '11 at 09:36
possible duplicate of [Does array_a contain all elements of array_b](http://stackoverflow.com/questions/4945049/does-array-a-contain-all-elements-of-array-b) — hakre, Jul 22 '11 at 09:37

score 4 · Answer 1 · edited Jul 22 '11 at 09:30

4

array_diff^[Docs] returns an array containing all the entries from the first array that are not present in any of the other arrays:

$return = (bool) count(array_diff($ar, $xy));

edited Jul 22 '11 at 09:30

hakre

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answered Jul 22 '11 at 09:07

rabudde

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no need for the ternary here; guess what count( ... ) > 0 gives you ;) – wonk0 Jul 22 '11 at 09:08
it gives me the number of elements in `$ar` which are not in `$xy` – rabudde Jul 22 '11 at 09:11
count( ... ) gives you the number; count( ... ) > 0 gives you a boolean – wonk0 Jul 22 '11 at 09:13
@rabudde The evaluation of the `count(...) > 0` already gives you your boolean value. No need for the manual assignment: `$return = (count(array_diff($ar, $xy)) > 0);` – Brendan Bullen Jul 22 '11 at 09:14
1

Just cast. Everything non-0 is true. – hakre Jul 22 '11 at 09:24

Markus · Answer 2 · 2011-07-22T09:17:07.330

2

You might use array_intersect

With some additional code (thanks Brendan):

return (count($ar) == count(array_intersect($xy, $ar)));

edited Jul 22 '11 at 09:17

answered Jul 22 '11 at 09:07

Markus

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Good answer but some code would be useful. Maybe: `return (count($ar) == count(array_intersect($xy,$ar)));`? – Brendan Bullen Jul 22 '11 at 09:12

score 0 · Answer 3 · answered Jul 22 '11 at 09:06

0

$found = true;
foreach ($ar as $r) {
    if (!in_array($r, $xy)) {
        $found = false;
        break;
    }
}

answered Jul 22 '11 at 09:06

Grim...

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JK. · Answer 4 · 2011-07-22T09:13:10.663

0

function array_equal($ar, $xy) {
  return !array_diff($ar, $xy) && !array_diff($ar, $xy);
}

This is how you use it.

if(array_equal($ar, $xy) {
  // etc...
}

edited Jul 22 '11 at 09:13

answered Jul 22 '11 at 09:06

JK.

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score 0 · Answer 5 · answered Jul 22 '11 at 09:08

function in_array_all($x, $y){

    $true = 0;
    $count = count($x);

    foreach($x as $key => $value){
        if(in_array($value, $y)) $true++;
    }

    return ($true == $count)? true: false;

}

$ar = array("a","b","c"); $xy = array("a","b","c","d","e");

echo in_array_all($ar, $xy);

find all array elements in another array

5 Answers5

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