声明函数时PHP的参数顺序

Question

This is a curiosity question. When creating a function, is there a recommended way to order the parameters? I mean, if I am going to create a function that receives 3 parameters, lets say int $a, $str b and $mixed $c, is there a reason to pick one order over another? like prefer function f($a, $b, $c) instead of function f($c, $b, $c) based on whatever? like the parameter types or anything else?

I know that optional parameters must always go at the end, but apart of that, is there any standard or practical recommendations that would affect performance or something?

In short, I only want to know if the order of the parameters of the function is always arbitrary or not.

NOTE: my question is about when functions are declared only.

Answer 1

They are relatively arbitrary, however there's a two main methodologies I've seen. The least common is "Order of Use", this only makes sense in sequential functions, where $this comes before $that.

However the typical way is something along the lines of "most important" or required arguments. You don't want important, optional, optional, optional, optional, optional, important - because then you'll need the optional ones set to '' or null or false in order to define the last important one.

Something like function test( $data_key, $number_of_results = 5, $classes = '' ){} makes sense because you can call test( 'my_key' ); and get arguably usable results.

Where if it was function test( $number_of_results = 5, $classes = '', $data_key ){}, you would make the semi-optional arguments before data_key required in a sense that they have to be passed to the function first: test( 5, '', 'my_key' );