问题：将列表中的项目连接到字符串
有没有更简单的方法将列表中的字符串项连接为单个字符串？我可以使用该str.join()功能吗？
例如，这是输入['this','is','a','sentence']，这是所需的输出this-is-a-sentence
sentence = ['this','is','a','sentence']
sent_str = ""
for i in sentence:
sent_str += str(i) + "-"
sent_str = sent_str[:-1]
print sent_str
Is there a simpler way to concatenate string items in a list into a single string? Can I use the str.join() function?
E.g. this is the input ['this','is','a','sentence'] and this is the desired output this-is-a-sentence
sentence = ['this','is','a','sentence']
sent_str = ""
for i in sentence:
sent_str += str(i) + "-"
sent_str = sent_str[:-1]
print sent_str
回答 0
用途join：
>>> sentence = ['this','is','a','sentence']
>>> '-'.join(sentence)
'this-is-a-sentence'
Use join:
>>> sentence = ['this','is','a','sentence']
>>> '-'.join(sentence)
'this-is-a-sentence'
回答 1
将python列表转换为字符串的更通用的方法是：
>>> my_lst = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> my_lst_str = ''.join(map(str, my_lst))
>>> print(my_lst_str)
'12345678910'
A more generic way to convert python lists to strings would be:
>>> my_lst = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> my_lst_str = ''.join(map(str, my_lst))
>>> print(my_lst_str)
'12345678910'
回答 2
对于初学者来说，了解join为什么是字符串方法非常有用
。
一开始很奇怪，但此后非常有用。
连接的结果始终是一个字符串，但是要连接的对象可以有多种类型（生成器，列表，元组等）。
.join更快，因为它只分配一次内存。比经典串联更好（请参阅扩展说明）。
一旦学习了它，它就会非常舒适，您可以执行以下技巧来添加括号。
>>> ",".join("12345").join(("(",")"))
Out:
'(1,2,3,4,5)'
>>> list = ["(",")"]
>>> ",".join("12345").join(list)
Out:
'(1,2,3,4,5)'
It’s very useful for beginners to know
why join is a string method.
It’s very strange at the beginning, but very useful after this.
The result of join is always a string, but the object to be joined can be of many types (generators, list, tuples, etc).
.join is faster because it allocates memory only once. Better than classical concatenation (see, extended explanation).
Once you learn it, it’s very comfortable and you can do tricks like this to add parentheses.
>>> ",".join("12345").join(("(",")"))
Out:
'(1,2,3,4,5)'
>>> list = ["(",")"]
>>> ",".join("12345").join(list)
Out:
'(1,2,3,4,5)'
回答 3
尽管@Burhan Khalid的回答很好，但我认为这样更容易理解：
from str import join
sentence = ['this','is','a','sentence']
join(sentence, "-")
join（）的第二个参数是可选的，默认为“”。
编辑：此功能已在Python 3中删除
Although @Burhan Khalid’s answer is good, I think it’s more understandable like this:
from str import join
sentence = ['this','is','a','sentence']
join(sentence, "-")
The second argument to join() is optional and defaults to ” “.
EDIT: This function was removed in Python 3
回答 4
我们可以指定如何连接字符串。除了使用’-‘，我们还可以使用”
sentence = ['this','is','a','sentence']
s=(" ".join(sentence))
print(s)
We can specify how we have to join the string. Instead of ‘-‘, we can use ‘ ‘
sentence = ['this','is','a','sentence']
s=(" ".join(sentence))
print(s)
回答 5
我们还可以使用Python的reduce函数：
from functools import reduce
sentence = ['this','is','a','sentence']
out_str = str(reduce(lambda x,y: x+"-"+y, sentence))
print(out_str)
We can also use Python’s reduce function:
from functools import reduce
sentence = ['this','is','a','sentence']
out_str = str(reduce(lambda x,y: x+"-"+y, sentence))
print(out_str)
回答 6
def eggs(someParameter):
del spam[3]
someParameter.insert(3, ' and cats.')
spam = ['apples', 'bananas', 'tofu', 'cats']
eggs(spam)
spam =(','.join(spam))
print(spam)
def eggs(someParameter):
del spam[3]
someParameter.insert(3, ' and cats.')
spam = ['apples', 'bananas', 'tofu', 'cats']
eggs(spam)
spam =(','.join(spam))
print(spam)
