PHP Function with Optional Parameters

I've written a PHP function that can accept 10 parameters, but only 2 are required. Sometimes, I want to define the eighth parameter, but I don't want to type in empty strings for each of the parameters until I reach the eighth.

One idea I had was to pass an abstracted function with an array of parameters which passes it along to the real function.

Is there a better way to set up the function so I can pass in only the parameters I want?

Solution 1:

What I have done in this case is pass an array, where the key is the parameter name, and the value is the value.

$optional = array(
  "param" => $param1,
  "param2" => $param2
);

function func($required, $requiredTwo, $optional) {
  if(isset($optional["param2"])) {
    doWork();
  }
}

Solution 2:

Make the function take one parameter: an array. Pass in the actual parameters as values in the array.

Edit: the link in Pekka's comment just about sums it up.

Solution 3:

To accomplish what you want, use an array Like Rabbot said (though this can become a pain to document/maintain if used excessively). Or just use the traditional optional args.

//My function with tons of optional params
function my_func($req_a, $req_b, $opt_a = NULL, $opt_b = NULL, $opt_c = NULL)
{
  //Do stuff
}
my_func('Hi', 'World', null, null, 'Red');

However, I usually find that when I start writing a function/method with that many arguments - more often than not it is a code smell, and can be re-factored/abstracted into something much cleaner.

//Specialization of my_func - assuming my_func itself cannot be refactored
function my_color_func($reg_a, $reg_b, $opt = 'Red')
{
  return my_func($reg_a, $reg_b, null, null, $opt);
}
my_color_func('Hi', 'World');
my_color_func('Hello', 'Universe', 'Green');

Solution 4:

You can just set the default value to null.

<?php
function functionName($value, $value2 = null) {
// do stuff
}

Solution 5:

In PHP 5.6 and later, argument lists may include the ... token to denote that the function accepts a variable number of arguments. The arguments will be passed into the given variable as an array; for example:

Example Using ... to access variable arguments

<?php
function sum(...$numbers) {
    $acc = 0;
    foreach ($numbers as $n) {
        $acc += $n;
    }
    return $acc;
}

echo sum(1, 2, 3, 4);
?>

The above example will output:

Variable-length argument lists PHP Documentation