Calling functions with multiple arguments in php

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I have defined a php function: 

function my_function($text = '', $relative = false, $icon = true) {
//do something
}

It works as expected with default values. But when I want to change the value of one variable it doesn’t work:

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my_function($icon = false); // this doesn't change anything

I have to call it with all variables to make changes take effect: 

my_function($text = '', $relative = false, $icon = false); // this changes the output

I am working in php 5.4.1 and WordPress. What I do wrong? Thanks.

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4 comments

  1. You must provide values for any default arguments to the left (in function signature) of the argument you want to change.

    So given the function:

    function my_function($text = '', $relative = false, $icon = true) {
//do something
}

    Here are some examples:

    // $text = "foo", $relative = false, $icon = true
my_function("foo"); 

// $text = "", $relative = true, $icon = true
my_function("", true) 

// $text = "", $relative = false, $icon = false
my_function("", false, false) 

  2. my_function($icon = false);

    You can’t do that in PHP. Well, you can, but it doesn’t do what you think it does. What this does is:

    1. Sets $icon to false
    2. Passes false as the 1st parameter to my_function

    If you want to change the third parameter, you need to also pass the first two.

    my_function('', false, true);

    Note: I think it’s python that lets you call functions like that, to set only the Xth parameter.

  3. Nothing wrong, that’s how PHP works.
    And when you’re calling a function, you shouldn’t put variables in the parameter list as you might get undesired results as the variables will be assigned those values. So, this is fine: 

    my_function('', false, false);

    or: 

    my_function($text, $relative, $icon);

    or anything in between, no need to assign values.

  4. You may use below code: 

    <?php

function my_function($arg = array("text"=>'Default',"relative"=>false,"icon"=>false))
{
  extract($arg);
      $text = isset($text)?$text:"";
      $relative = isset($relative)? $relative : false;
      $icon = isset($icon)? $icon : false;

      //do something

}

my_function(array("icon"=>true));

?>

    WARNING: if you use this way. you should initialise the variable or check the if it is exists.