I currently have a string that I want to edit by adding spaces between each character, so I currently have s = 'abcdefg' and I want it to become s = 'a b c d e f g'. Is there any easy way to do this using loops?
我目前有一个字符串，我想通过在每个字符之间添加空格来编辑，所以我目前有s ='abcdefg'，我希望它变成s ='a b c d e f g'。有没有简单的方法来使用循环？
2 个解决方案
#1
15
>>> ' '.join('abcdefg')
'a b c d e f g'
#2
2
You did specify "using loops"
你确实指定了“使用循环”
A string in Python is an iterable, meaning you can loop over it.
Python中的字符串是可迭代的，这意味着您可以循环它。
Using loops:
使用循环：
>>> s = 'abcdefg'
>>> s2=''
>>> for c in s:
... s2+=c+' '
>>> s2
'a b c d e f g ' #note the trailing space there...
Using a comprehension, you can produce a list:
使用理解，您可以生成一个列表：
>>> [e+' ' for e in s]
['a ', 'b ', 'c ', 'd ', 'e ', 'f ', 'g '] #note the undesired trailing space...
You can use map:
你可以使用map：
>>> import operator
>>> map(operator.concat,s,' '*len(s))
['a ', 'b ', 'c ', 'd ', 'e ', 'f ', 'g ']
Then you have that pesky list instead of a string and a trailing space...
然后你有那个讨厌的列表而不是字符串和尾随空格......
You could use a regex:
你可以使用正则表达式：
>>> import re
>>> re.sub(r'(.)',r'\1 ',s)
'a b c d e f g '
You can even fix the trailing space with a regex:
您甚至可以使用正则表达式修复尾随空格：
>>> re.sub(r'(.(?!$))',r'\1 ',s)
'a b c d e f g'
If you have a list, use join to produce a string:
如果您有一个列表，请使用join生成一个字符串：
>>> ''.join([e+' ' for e in s])
'a b c d e f g '
You can use the string.rstrip() string method to remove the unwanted trailing whitespace:
您可以使用string.rstrip（）字符串方法删除不需要的尾随空格：
>>> ''.join([e+' ' for e in s]).rstrip()
'a b c d e f g'
You can even write to a memory buffer and get a string:
您甚至可以写入内存缓冲区并获取字符串：
>>> from cStringIO import StringIO
>>> fp=StringIO()
>>> for c in s:
... st=c+' '
... fp.write(st)
...
>>> fp.getvalue().rstrip()
'a b c d e f g'
But since join works on lists or iterables, you might as well use join on the string:
但是由于join适用于列表或迭代，你不妨在字符串上使用join：
>>> ' '.join('abcdefg')
'a b c d e f g' # no trailing space, simple!
The use of join in this way is one of the most important Python idioms.
以这种方式使用join是最重要的Python习语之一。
Use it.
用它。
There are performance considerations as well. Read this comparison on various string concatenation methods in Python.
还有性能方面的考虑因素。阅读Python中各种字符串连接方法的比较。
#1
15
>>> ' '.join('abcdefg')
'a b c d e f g'
#2
2
You did specify "using loops"
你确实指定了“使用循环”
A string in Python is an iterable, meaning you can loop over it.
Python中的字符串是可迭代的，这意味着您可以循环它。
Using loops:
使用循环：
>>> s = 'abcdefg'
>>> s2=''
>>> for c in s:
... s2+=c+' '
>>> s2
'a b c d e f g ' #note the trailing space there...
Using a comprehension, you can produce a list:
使用理解，您可以生成一个列表：
>>> [e+' ' for e in s]
['a ', 'b ', 'c ', 'd ', 'e ', 'f ', 'g '] #note the undesired trailing space...
You can use map:
你可以使用map：
>>> import operator
>>> map(operator.concat,s,' '*len(s))
['a ', 'b ', 'c ', 'd ', 'e ', 'f ', 'g ']
Then you have that pesky list instead of a string and a trailing space...
然后你有那个讨厌的列表而不是字符串和尾随空格......
You could use a regex:
你可以使用正则表达式：
>>> import re
>>> re.sub(r'(.)',r'\1 ',s)
'a b c d e f g '
You can even fix the trailing space with a regex:
您甚至可以使用正则表达式修复尾随空格：
>>> re.sub(r'(.(?!$))',r'\1 ',s)
'a b c d e f g'
If you have a list, use join to produce a string:
如果您有一个列表，请使用join生成一个字符串：
>>> ''.join([e+' ' for e in s])
'a b c d e f g '
You can use the string.rstrip() string method to remove the unwanted trailing whitespace:
您可以使用string.rstrip（）字符串方法删除不需要的尾随空格：
>>> ''.join([e+' ' for e in s]).rstrip()
'a b c d e f g'
You can even write to a memory buffer and get a string:
您甚至可以写入内存缓冲区并获取字符串：
>>> from cStringIO import StringIO
>>> fp=StringIO()
>>> for c in s:
... st=c+' '
... fp.write(st)
...
>>> fp.getvalue().rstrip()
'a b c d e f g'
But since join works on lists or iterables, you might as well use join on the string:
但是由于join适用于列表或迭代，你不妨在字符串上使用join：
>>> ' '.join('abcdefg')
'a b c d e f g' # no trailing space, simple!
The use of join in this way is one of the most important Python idioms.
以这种方式使用join是最重要的Python习语之一。
Use it.
用它。
There are performance considerations as well. Read this comparison on various string concatenation methods in Python.
还有性能方面的考虑因素。阅读Python中各种字符串连接方法的比较。