PHP Function with Optional Parameters

user_481826 0
Viewed 244373

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?

parameter-passing function php
15 Answers

You can just set the default value to null.

<?php
function functionName($value, $value2 = null) {
// do stuff
}
user_97227010

Starting with PHP 8 you are able to use named arguments:

function namedParameters($paramOne, $paramTwo, $paramThree = 'test', $paramFour = null)
{
    dd($paramOne, $paramTwo, $paramThree, $paramFour);
}

We can now call this function with the required params and only the optinal params, that we want to differ from the default value which we specified in the function.

namedParameters('one', 'two', paramFour: 'four');

Result:

// "one", "two", "test", "four"
user_114853260 
function yourFunction($var1, $var2, $optional = Null){
   ... code
}

You can make a regular function and then add your optional variables by giving them a default Null value.

A Null is still a value, if you don't call the function with a value for that variable, it won't be empty so no error.

user_94533230

PHP allows default arguments (link). In your case, you could define all the parameters from 3 to 8 as NULL or as an empty string "" depending on your function code. In this way, you can call the function only using the first two parameters.

For example:

<?php
  function yourFunction($arg1, $arg2, $arg3=NULL, $arg4=NULL, $arg5=NULL, $arg6=NULL, $arg7=NULL, $arg8=NULL){
echo $arg1;
echo $arg2;
if(isset($arg3)){echo $arg3;}
# other similar statements for $arg4, ...., $arg5
if(isset($arg8)){echo $arg8;}
}
user_107046190

Just set Null to ignore parameters that you don't want to use and then set the parameter needed according to the position.

 function myFunc($p1,$p2,$p3=Null,$p4=Null,$p5=Null,$p6=Null,$p7=Null,$p8=Null){
    for ($i=1; $i<9; $i++){
        $varName = "p$i";
        if (isset($$varName)){
            echo $varName." = ".$$varName."<br>\n";
        }
    }
}   

myFunc( "1", "2", Null, Null, Null, Null, Null, "eight" );
user_138561620
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