尝试在Python中扩展列表时出现类型错误 [英] Type error when trying to extend a list in Python

问题描述

我需要了解原因:

years = range(2010,2016)
years.append(0)

是可能的，返回:

[2010,2011,2012,2013,2014,2015,0]

和

years = range(2010,2016).append(0)

或

years = [0].extend(range(2010,2016))

行不通吗?

我了解这是我收到的消息中的类型错误.但我想在此后面提供更多解释.

I understand that it is a type error from the message I got. But I'd like to have a bit more explanations behind that.

推荐答案

您正在存储list.append()或list.extend()方法的结果；都更改列表到位，并返回None.他们不会不再次返回列表对象.

You are storing the result of the list.append() or list.extend() method; both alter the list in place and return None. They do not return the list object again.

不存储None结果；存储range()结果， then 扩展或追加.或者，使用串联:

Do not store the None result; store the range() result, then extend or append. Alternatively, use concatenation:

years = range(2010, 2016) + [0]
years = [0] + range(2010, 2016)

请注意，我假设您使用的是Python 2(否则您的第一个示例将无法正常工作).在Python 3中，range()不会产生列表.您必须使用list()函数将其转换为一个:

Note that I'm assuming you are using Python 2 (your first example would not work otherwise). In Python 3 range() doesn't produce a list; you'd have to use the list() function to convert it to one:

years = list(range(2010, 2016)) + [0]
years = [0] + list(range(2010, 2016))

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