How to Override Specific Default Arguments in PHP Functions?

Advanced Default Argument Usage in PHP Functions

In PHP, default arguments provide flexibility to functions, allowing developers to define fallback values for parameters. However, when dealing with multiple default arguments, it can be confusing to selectively override certain arguments while retaining the default values for others.

Question:

Say we have a function with default arguments:

<code class="php">function foo($blah, $x = "some value", $y = "some other value") {
    // code here!
}</code>

How can we use the default argument for $x but set a different value for $y?

Solution:

The key to achieving this is to modify the function declaration:

<code class="php">function foo($blah, $x = null, $y = null) {
    if (null === $x) {
        $x = "some value";
    }

    if (null === $y) {
        $y = "some other value";
    }

    code here!
}</code>

This adjustment allows you to call the function as follows:

<code class="php">foo('blah', null, 'non-default y value');</code>

In this case, $x retains its default value, while $y is overridden with the specified non-default value.

Additional Considerations:

• By default, PHP parameters only work as the last arguments in a function. It's not possible to omit one parameter and override the value of a parameter that follows it.
• When dealing with varying numbers of parameters of different types, consider declaring a function with a variable number of arguments, as shown in the following example:

<code class="php">public function __construct($params = null) {
    // code here!
}</code>

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