“NoneType"对象不可下标? [英] 'NoneType' object is not subscriptable?

问题描述

list1 = ["name1", "info1", 10]
list2 = ["name2", "info2", 30]
list3 = ["name3", "info3", 50]
MASTERLIST = [list1, list2, list3]


def printer(lst):
    print ("Available Lists:")
    for x in range(len(lst)):
        print (lst[x])[0]

此代码返回'NoneType' 对象不可下标"；我尝试运行时出错

This code is returning the "'NoneType' object is not subscriptable" error when I try and run

printer(MASTERLIST)

我做错了什么?

推荐答案

print() 函数返回 None.您正在尝试索引 None.您不能，因为 'NoneType' 对象不可下标.

The print() function returns None. You are trying to index None. You can not, because 'NoneType' object is not subscriptable.

将 [0] 放在括号内.现在您正在打印所有内容，而不仅仅是第一学期.

Put the [0] inside the brackets. Now you're printing everything, and not just the first term.

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