使用.append在Python中迭代一个不断增长的数字列表

Question

这两种方法都返回None类型；它们的目的是在列表中添加一个比最终整数高1的新数字。双打印语句只是为了测试循环中代码的可行性。我做错了什么而没有得到想要的结果

方法1:

number_list = [1,2,3,4,5,6,7,8]
number_list = number_list.append(number_list[-1]+1)
print(number_list)
print(number_list)

方法2:

number_list = [1,2,3,4,5,6,7,8]
number_list = number_list.append(number_list[0]+number_list[-1])
print(number_list)
print(number_list)

Answer 1

.append返回none，这就是您将number_list设置为的内容。相反，使用该方法时不要将其设置为number_list，这样可以很好地工作

>>> number_list = [1,2,3,4,5,6,7,8]
>>> number_list
[1, 2, 3, 4, 5, 6, 7, 8]
>>> number_list.append(number_list[-1]+1)
>>> number_list
[1, 2, 3, 4, 5, 6, 7, 8, 9]

You might have noticed that methods like insert, remove or sort that only modify the list have no return value printed – they return the default None. 1 This is a design principle for all mutable data structures in Python. [source]

Answer 2

您不需要numberlist=numberlist.append（…）

只是

numberlist.append(..)