如果列表索引存在，则执行 X [英] If list index exists, do X

问题描述

在我的程序中，用户输入数字n，然后输入n个字符串，这些字符串存储在一个列表中.

In my program, user inputs number n, and then inputs n number of strings, which get stored in a list.

我需要编写这样的代码，如果某个列表索引存在，则运行一个函数.

I need to code such that if a certain list index exists, then run a function.

由于我嵌套了关于 len(my_list) 的 if 语句，这变得更加复杂.

This is made more complicated by the fact that I have nested if statements about len(my_list).

这是我现在所拥有的简化版本，但不起作用:

Here's a simplified version of what I have now, which isn't working:

n = input ("Define number of actors: ")

count = 0

nams = []

while count < n:
    count = count + 1
    print "Define name for actor ", count, ":"
    name = raw_input ()
    nams.append(name)

if nams[2]: #I am trying to say 'if nams[2] exists, do something depending on len(nams)
    if len(nams) > 3:
        do_something
    if len(nams) > 4
        do_something_else

if nams[3]: #etc.

推荐答案

使用列表的长度 len(n) 比检查 len(n) 的长度更有用吗?code>n[i] 每个可能的长度?

Could it be more useful for you to use the length of the list len(n) to inform your decision rather than checking n[i] for each possible length?

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