Php function use only specified arguments

Question

Are all the arguments of a php function required? i mean if i have a function that takes 5 arguments like this

function MyFunction($conditionArg, $arg1, $arg2, $arg3, $arg4) {
    if($conditionArg == "something") {
        // use arguments 1 and 2
    }
    elseif($conditionArg == "something else") {
        // use arguments 3 and 4
    }
}

So my question is: When i call that function can i provide only the needed arguments like this

MyFunction("something", $arg1 value, $arg2 value)

score 3 · Accepted Answer · edited May 23 '17 at 12:28

In such cases, you can specify default arguments. If the arguments aren't specified during the function call, then their default value will be used.

function MyFunction($conditionArg, $arg1=null, $arg2=null, $arg3=null, $arg4=null) {
    if($conditionArg == "something") {
        // use arguments 1 and 2
    }
    elseif($conditionArg == "something else") {
        // use arguments 3 and 4
    }
}

Now, all the following function calls will work fine:

MyFunction("something");
MyFunction("something", $arg1);
MyFunction("something", $arg1, $arg2);
MyFunction("something", $arg1, $arg2, $arg3);
MyFunction("something", $arg1, $arg2, $arg3, $arg4);

See also: Should my PHP functions accept an array of arguments or should I explicitly request arguments?

picus · Answer 2 · 2013-12-16T18:44:55.567

You can set the default value when declaring the function:

function MyFunction($conditionArg, $arg1=false, $arg2=false, $arg3=false, $arg4=false) {
    if($conditionArg == "something") {
        // use arguments 1 and 2
    }
    elseif($conditionArg == "something else") {
        // use arguments 3 and 4
    }
}

In the above example only the $conditionArg is now required, all else would default to false in the function's scope.

It can be defaulted to anything, string int, null etc.

In an example like this, Another option is to mimic a pythonic kwargs array and pass one argument as an array only including the required arguments as array elements...

MyFunction($args = array())
{
  if(isset($args['condition']))
  {
    if($args['condition'] === "something")
    {
    //make hay
    }
    elseif($args['condition'] === "derp")
    {
    //make a different kind of hay
    }

  }

}

to take the second example one step further, if the first item is always required, then pass that first separately and pass the argument array second:

MyFunction($conditionArg, $args = array())
{

    if($condition === "something")
    {
      //use $args['one'], $args['two']
    }
    elseif($condition === "derp")
    {
      //use $args['three'], $args['four']
    }  

}

Php function use only specified arguments

2 Answers2