php return all the key if key = true code example

Example 1: php key exists

// Here's our fruity array
$fruits = ['apple', 'pear', 'banana'];

// Use it in an `if` statement
if (array_key_exists("banana", $fruits)) {
 // Do stuff because `banana` exists
}

// Store it for later use
$exists = array_key_exists("peach", $fruits);

Example 2: php array all keys empty

array('key1' => null, 'key2' => null, 'key3' => null, 'key4' => null)
if (!array_filter($array)) {
    // all values are empty (where "empty" means == false)
}