Merge “Defaults” array with “Input” array? PHP Which Function?

Question

Lets say you are having a user provide information.

Array 1

But not all is required. So you have defaults.

Array 2
         


        

Answer 1

If you just want to keep the options that you expect and discard the rest you may use a combination of array_merge and array_intersect_key.

 1,
        'b' => null,
    ];

    $mergedParams = array_merge(
        $defaults,
        array_intersect_key($options, $defaults)
    );

    return $mergedParams;
}


var_dump(foo([
    'a' => 'keep me',
    'c' => 'discard me'
]));

// => output
//
// array(2) {
//   ["a"]=>
//   string(7) "keep me"
//   ["b"]=>
//   NULL
// }

If you instead want to keep any extra key then array_merge($defaults, $options) will do just fine.