在 Python 3 中迭代数组 [英] Iterating over arrays in Python 3

问题描述

我已经有一段时间没有编写代码并尝试重新使用 Python.我正在尝试编写一个简单的程序，通过将每个数组元素值添加到总和来对数组求和.这就是我所拥有的:

I haven't been coding for awhile and trying to get back into Python. I'm trying to write a simple program that sums an array by adding each array element value to a sum. This is what I have:

def sumAnArray(ar):
    theSum = 0
    for i in ar:
        theSum = theSum + ar[i]
    print(theSum)
    return theSum

我收到以下错误:

line 13, theSum = theSum + ar[i]
IndexError: list index out of range

我发现我想要做的事情显然就是这么简单:

I found that what I'm trying to do is apparently as simple as this:

sum(ar)

但显然我无论如何都没有正确地遍历数组，而且我认为这是我需要为其他目的正确学习的东西.谢谢！

But clearly I'm not iterating through the array properly anyway, and I figure it's something I will need to learn properly for other purposes. Thanks!

推荐答案

当你像你一样在数组中循环时，你的 for 变量(在这个例子中是 i)是你数组的当前元素.

When you loop in an array like you did, your for variable(in this example i) is current element of your array.

例如如果你的ar是[1,5,10]，则每次迭代中的i值为1、5 和 10.因为你的数组长度是 3，所以你可以使用的最大索引是 2.所以当 i = 5 你得到 IndexError.你应该把你的代码改成这样:

For example if your ar is [1,5,10], the i value in each iteration is 1, 5, and 10. And because your array length is 3, the maximum index you can use is 2. so when i = 5 you get IndexError. You should change your code into something like this:

for i in ar:
    theSum = theSum + i

或者如果你想使用索引，你应该创建一个范围从 0 ro array length - 1.

Or if you want to use indexes, you should create a range from 0 ro array length - 1.

for i in range(len(ar)):
    theSum = theSum + ar[i]

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