php when and how to use (!empty) code example

Example: php empty

/*
 * Determine whether a variable is considered to be empty.
 * A variable is considered empty if it does not exist or if its value equals false (is a falsey).
 */
empty('');      // true
empty('0');     // true
empty(0);       // true
empty(null);    // true
empty([]);      // true
empty('false'); // false
empty('true');  // false