Compare two associative arrays regarding the order of keys
arrays, associative-array, php
Solution
As described under array operators, what you want is the `===` equality operator.
if ($array1 === $array2) {
echo "same key pairs and same element order\n";
}
Problem
Suppose, we have 2 associative arrays: ``` <?php $array1 = array( 1 => 2, 2 => 1, ); $array2 = array( 2 => 1, 1 => 2, ); ``` They contain same elements, but in different order. I wanted to write a comparison function, that will give true only if: - Arrays have the same key => value pairs. - Order of pairs is the same. So, I tried the following: 1 try ``` if ($array1 == $array2) { print "equal\n"; } ``` Prints: equal 2 try ``` print count(array_diff_assoc($array1, $array1)); ``` Prints: 0 My custom function Then I created the following function: ``` function compare(&$array1, &$array2) { $n1 = count($array1); $n2 = count($array2); if ($n1 == $n2) { $keys1 = array_keys($array1); $keys2 = array_keys($array2); for ($i = 0; $i < $n1; ++$i) { if ($keys1[$i] == $keys2[$i]) { if ($array1[$keys1[$i]] != $array2[$keys2[$i]]) { return false; } } else { return false; } } return true; } else { return false; } } ``` This works correctly, but it won't work, when we want this strict comparison applied for nested arrays of arrays because of `!=` operator in this if: ``` if ($array1[$keys1[$i]] != $array2[$keys2[$i]]) { return false; } ``` This can be fixed, using a recursive function, switching by type of data. But this simplified version was ok for me. Is there any standard solution for this type of comparison?