Python “NoneType”对象不可下标？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/18866657/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
'NoneType' object is not subscriptable?
提问by user2786555
list1 = ["name1", "info1", 10]
list2 = ["name2", "info2", 30]
list3 = ["name3", "info3", 50]
MASTERLIST = [list1, list2, list3]
def printer(list):
print ("Available Lists:")
listlen = (len(list))
for x in range(listlen):
print (list[x])[0]
This code is returning the "'NoneType' object is not subscriptable" error when I try and run printer(MASTERLIST). What did I do wrong?
当我尝试运行printer(MASTERLIST). 我做错了什么？
回答by Ethan Furman
The [0]needs to be inside the ).
该[0]需求在里面的)。
回答by TerryA
The print()function returns None. You are trying to index None. You can not, because 'NoneType' object is not subscriptable.
该print()函数返回None。您正在尝试索引 None。你不能，因为'NoneType' object is not subscriptable.
Put the [0]inside the brackets. Now you're printing everything, and not just the first term.
把[0]里面的括号。现在您正在打印所有内容，而不仅仅是第一项。
回答by Matthias
Don't use listas a variable name for it shadows the builtin.
不要list用作变量名，因为它会影响内置函数。
And there is no need to determine the length of the list. Just iterate over it.
并且不需要确定列表的长度。只需迭代它。
def printer(data):
for element in data:
print(element[0])
Just an addendum: Looking at the contents of the inner lists I think they might be the wrong data structure. It looks like you want to use a dictionary instead.
只是一个附录：查看内部列表的内容，我认为它们可能是错误的数据结构。看起来您想改用字典。
回答by Cam92
Point A: Don't use list as a variable name Point B: You don't need the [0] just
A 点：不要使用列表作为变量名 B 点：您不需要 [0] 只是
print(list[x])
回答by Reizz
The indexing e.g. [0] should occour inside of the print...
索引例如 [0] 应该出现在打印内部...
回答by Joshua Nixon
list1 = ["name1", "info1", 10]
list2 = ["name2", "info2", 30]
list3 = ["name3", "info3", 50]
def printer(*lists):
for _list in lists:
for ele in _list:
print(ele, end = ", ")
print()
printer(list1, list2, list3)
