Check If Array Is Associative

This function checks if an array is associative. It compares the array’s keys with a range of integers from 0 to one less than the count of the array. If they’re the same, it means the array is indexed, not associative. This function is useful for determining how to process an array depending on its structure.

PHP Function:

function isAssocArray(array $arr) { return array_keys($arr) !== range(0, count($arr) - 1); }

// Example
echo isAssocArray(['a', 'b', 'c']); // false
echo isAssocArray(['a' => 1, 'b' => 2, 'c' => 3]); // true