在python中将数组作为参数传递

Pass array as argument in python

提问by user12345

I am new to python. Now I need to declare the array of size 20 and pass the array to a function.

我是python的新手。现在我需要声明大小为 20 的数组并将该数组传递给一个函数。

The function expecting the array is as:

期望数组的函数是：

function(*args)

The argsis an input to the function().

的args是一个输入到function()。

Can anyone help me, how to pass array in python?

谁能帮我，如何在python中传递数组？

回答by PM 2Ring

When you say "array" I assume you mean a Python list, since that's often used in Python when an array would be used in other languages. Python actually has several array types: list, tuple, and array; the popular 3rd-party module Numpyalso supplies an array type.

当您说“数组”时，我假设您的意思是 Python list，因为当数组在其他语言中使用时，它经常在 Python 中使用。Python 实际上有几种数组类型：list, tuple, 和array; 流行的第 3 方模块Numpy也提供了一个数组类型。

To pass a single list (or other array-like container) to a function that's defined with a single *argsparameter you need to use the *operator to unpack the list in the function call.

要将单个列表（或其他类似数组的容器）传递*args给使用单个参数定义的函数，您需要使用*运算符在函数调用中解压缩列表。

Here's an example that runs on Python 2 or Python 3. I've made a list of length 5 to keep the output short.

这是一个在 Python 2 或 Python 3 上运行的示例。我制作了一个长度为 5 的列表以保持输出简短。

def function(*args):
    print(args)
    for u in args:
        print(u)

#Create a list of 5 elements
a = list(range(5))
print(a)

function(*a)        

output

输出

[0, 1, 2, 3, 4]
(0, 1, 2, 3, 4)
0
1
2
3     
4 

Note that when functionprints argsthe output is shown in parentheses (), not brackets []. That's because the brackets denote a list, the parentheses denote a tuple. The *ain the call to functionunpacks the alist into separate arguments, but the *argin the functiondefinition re-packs them into a tuple.

请注意，function打印时args输出显示在括号中()，而不是括号中[]。那是因为括号表示一个列表，括号表示一个元组。该*a呼叫到function拆包a列表为单独的参数，但*arg在function定义重新包装它们放入一个元组。

For more info on these uses of *please see Arbitrary Argument Listsand Unpacking Argument Listsin the Python tutorial. Also see What does ** (double star) and * (star) do for Python parameters?.

有关这些用途的详细信息*，请参阅任意参数列表和开箱参数列表在Python教程。另请参阅**（双星）和 *（星）对 Python 参数有何作用？.

回答by xio

Size doesn't matter.

大小无关紧要。

Just pass listto function.

只是传递list给函数。

def foo(mylist):
     # do whatever you want with array here
     pass

You don't need *argssequence unpacking for that purpose.

*args为此，您不需要序列解包。

回答by Marc Cabos

I think that what you need is easier than expected:

我认为您需要的比预期的要容易：

def arrayIn(arrayFunc):
    print(arrayFunc)

arraySize = 20
mineArray = [None]*arraySize
arrayIn(mineArray)