使用数组作为参数的缺点？ [关闭]

Question

I always use one array arguments to a function whenever I need more then 3 parameter.

Example: Consider a function call like this.

processSecondStage($stepTitle, $round, $entryId, $formId, $stepType, $stepAfterApproved, $assigneees, $stageToMove);

I always prefer the below one.

processSecondStage(array( 'stepTitle' => $title, 'round' => $round, 'stepAfterApproved' => $stepAfterApproved, 'entryId' => $_entryId, 'assigneees' => (array)$_POST['flow-asignee'], 'stageToMove' => $currentStep, 'formId' => $targetFormId, 'stepType' => 'approval' ));

Advantage (I might be wrong):

a) Can add more number of parameter

b) Readability

c) Order can be changed easily

d) Default parameter handling is easier

Disadvantage :

a) Code length is increase specially in case when we have less then 3-4 arguments.

Can anyone please help me Know more disadvantage of using the array parameter ?

Whenever I change other developer code (like I am going to do now), then I feel that there are some major disadvantage of using array as parameter because if that was not the case then it should have been a standard practice.

Although I have given example of PHP, but I find this in other language also on which I work.

Thank You.

Answer 1

Arrays are useful as a parameter when things you want to pass are closely related and do not make sense separately. A classical example is a Color that is defined by blue, green, red (and maybe gamma). Combining these parameters into an array (or object in javascript) allows you to swap it out easily.

Always using an array as the single parameter of a function makes you loose out on a parameter list an IDE can give you. For someone reading the code, it is quite a hell to figure out what needs to be passed to a function. It also opens the door to future creep (oh, this function was only making me coffee, but if I add another optional parameter it can also make me tea. Oh, and maybe I can let it make me dinner to. Why not add the functionality to order an attack helicopter too).

In a regular parameter list you can pass things by reference (function pushElement(array &$sortableArray, $element)). This is not expected in a regular array, if it is even possible.

The point about default values is kind of a moot point. Normal parameter lists allow type hinting and default values just fine:

function action(string $action = 'tickle', string $target = 'Polar bear') {
  print "I {$action} a {$target}";
}

A single parameter as array probably only really shines when passing some kind of static configuration. You keep the configuration of something separate from the actual code using it, making it easier to modify the configuration. At the same time you leverage the fact that you do not have to send 20 parameters in a very specific order.

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In your case the parameter list you give is wildly varied and long, which suggests that your function is doing way too much. Part of it should probably be moved to a constructor and part of it should probably be moved to some kind of Form class.