I have three arrays:
$arr_1 = array('a'=>1,'b'=>2);
$arr_11 = array('a'=>1, 'd'=>4);
$arr_2 = array('a'=>'aaa','b'=>'bbb', 'c'=>'ccc');
I want to check that all keys from $arr_1 exist in $arr_2.
someFunction($arr_1,$arr_2); //return true
someFunction($arr_11,$arr_2); //return false
I know how to do it with a "foreach" loop.
Is there a better way?
maybe
<?php
array_diff(array_keys($arr_1), array_keys($arr_11));
?>
shorter yes, faster dunno :)
Update from @deceze
<?php
array_diff_key($arr_1, $arr_11);
?>
You could use array_key_exists() or isset() in a while loop:
$found_missing_key = false
$keys = array_keys($array1);
foreach($keys as $key) {
if(!isset($array2[$key])) {
$found_missing_key = true;
break;
}
}
Write someFunction yourself, and use a loop inside. A loop and array_key_exists is the way to do this, but you can save yourself having to do it again in the future if you wrap it in a function.
UPDATE
function arrayKeyCompare($control, $variable) {
foreach (array_keys($control) as $key) {
if (!array_key_exists($key, $variable)) return false;
}
return true;
}
Here is an alternative approach to check if all keys in $arr1 are present in $arr2:
function check($v){
return array_key_exists($v,$arr_2);
}
count(array_filter(array_keys($arr_1),"check")) == count($arr_1); // true
Note that while you might not have write the loop out yourself, inevitably any sort of search for keys in an array is going to involve one.
array_diff()except the comparison is done on the keys instead of the values.