How can PHP developers ensure that variables are properly declared as arrays before using them in loops or operations?

PHP developers can ensure that variables are properly declared as arrays before using them in loops or operations by using the `is_array()` function to check if a variable is an array. If the variable is not an array, it can be converted to an empty array using the `array()` function. This ensures that the variable is always treated as an array, preventing errors when trying to access array-specific functions or properties.

// Check if variable is an array, if not, convert it to an empty array
if (!is_array($myArray)) {
    $myArray = array();
}

// Now $myArray is guaranteed to be an array and can be safely used in loops or operations