PHP将数组传递给函数

Question

I've seen a few people ask a similar question. But I do need a little more clarification on this particular subject.

I have several functions that pass several arguments. I even have a few that are about 10 arguments. (didn't initially plan it, simply grew over time)

I don't have any problems looking at my source code to find out what the 7th argument is, but it does get tedious. Most of the time I know what arguments to pass, just not the position.

I had a few ideas to simplify the process for me.

a) pass 1 argument, but divide everything with some delimiter. (but that's a bad idea!, since I still need to remember the position of each.

function myfunc('data|data|data|'){
          // explode the string
}

b) pass an array with key and values, and look for the key names inside my function, and act accordingly.

function myfunc(array('arg1' => 'blah blah', 'arg2' => 'more blah')){
  // loop through the array
}

c) keep it as it is.

function myfunc($arg1,$arg2,$arg3,$arg4,$arg5........){
// yay

}

So, I'm seeking other options and better ideas for handling functions with growing argument lists.

Answer 1

In my opinion, the best way to it is by passing in an associative array. That way you immediately see what each argument does. Just be sure to name them descriptively, not arg1 & arg2 .

Another advantage an associative array, is that you don't have to care about the order in which the arguments are being passed in.

Just remember that if you use an associative array, you lose PHP's native way of assigning default values, eg:

function doSomething($arg1 = TRUE, $arg2 = 55) { }

So, what you have to do is create your own set of default options, and then merge your arrays:

function doSomething( $props = array() )
{
    $props = array_merge(array(
        'arg1' => TRUE,
        'arg2' => 55
    ), $props);

    // Now use the $props array
}

Answer 2

go with the myfunc($options) form when you have many optional parameters that can be mixed and matched. Use array_merge_recursive with a default options array, and you'll be golden.

Answer 3

b）（关联数组）是迄今为止最容易，最适应的（因为它允许模拟默认关键字参数），并且最不容易出错的变体。

Answer 4

First, see if you can introduce paramter object . It not necesseary to replace all 7 parameters, but maybe you can lower their count.

Next, examine the function itself - why it needs so many parameters, maybe it just does to much things? Is Replace parameter with method / Replace parameter with explicit method applicable?

By the way, Refactoring is great reading!

Answer 5

根据函数的用途，有时传递一个对象是合适的。

Answer 6

Let's not talk about solution #1. You already say that it is bad...

I like the second idea of passing in this hash/associative array. It feels rubylike :) The thing you are doing is that you are giving up some checks that you would get for free. If you call a function and forget an argument the runtime complains and the script stops executing. In your scenario you would have to do all those checks inside your function: Are all necessary options given? Are the values the right types, etc?

I would say, the decision is up to your taste if it's just you working on the code. If others are working with you, I would ask them about their opinion. Until then, I would stick with the classic approach of having the function with 7 arguments

Answer 7

Associative array with keys as parameter names, order does not count (do not to forget you document which keys are expected):

function myFunc(array $args)
{
    # default values
    $args += array('arg1' => 'default1', 'arg2' => 'default2');
}

Sometimes you want to verify that you drop all unimportant keys from the input as well. A useful function for this is array_intersect_key ^Docs .

Answer 8

check this post about creating an ellipsis in PHP.
Creating an ellipsis in PHP

Answer 9

function myfunc($arg1,$arg2,$arg3,$arg4,$arg5........){

With the limited information provided, I would have to say keep it as is . The reason for this is that your function signature shows that none of your arguments have default values (they are all required).

If you make it an associative array, then you remove the parser's ability to warn about ill-called functions, ie:

Missing argument 2 for some_function, called in [etc.]

IDEs can help with function calling assistance if you have difficulty remembering all the arguments.

Basically, if it's a required argument, it should be in the function signature.