将字符串添加到列表 [英] Adding a string to a list

问题描述

>>> b = []
>>> c = '1234'
>>> b += c
>>> b
['1', '2', '3', '4']
>>> 

这是怎么回事?这不行吧?还是我缺少明显的东西?

What is happening here ? This should not work, right ? or am I missing something obvious?

>>> b = []
>>> c = '1234'
>>> b + c
Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    b + c
TypeError: can only concatenate list (not "str") to list
>>> 

然后a += b并不总是等同于a = a + b吗?

Then a += b is not always equivalent to a = a + b ?

推荐答案

字符串是可迭代的:元素是字符串的字符.在将可迭代项添加到列表时，可迭代项的 elements 会附加到列表中.

Strings are iterable: the elements are the string's characters. When you add an iterable to a list, the iterable's elements get appended to the list.

以下任何一项都可以满足您的期望(即追加字符串，而不用字符串的字符扩展列表):

Either of the following will do what you're expecting (i.e. append the string, not extend the list with the string's characters):

b += [c]

或

b.append(c)

这篇关于将字符串添加到列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！