python中删除空白字符

python 中删除字符串中的空白字符。

主要参考StackOverflow答案总结。

空白字符一般指以下几种字符：space, tab, linefeed, return, formfeed, and vertical tab。中英文对照表如下：

英文	space	tab	linefeed	return	formfeed	vertical tab
中文	空格	水平制表符	换行	回车	换页	垂直制表符
转义字符	’ ‘	‘\t’	‘\n’	‘\r’	‘\f’	‘\v’
ASCII name	SP	HT	NL	CR	FF	VT
English name	space	horizontal tab	newline	carriage return	form feed	vertical tab

去除空格

去除左右两边的空格

使用str.strip():

In [1]: sentence = ' hello  apple'

In [2]: sentence.strip()
Out[2]: 'hello  apple'

去除所有空格

使用str.replace()

In [3]: sentence = ' hello  apple'

In [4]: sentence.replace(" ", "")
Out[4]: 'helloapple'

去除空白字符

去除所有的空白字符

使用str.split()及join

In [10]: sentence = '  hello  apple   \n  \r   \t '

In [11]: "".join(sentence.split())
Out[11]: 'helloapple'

使用正则

In [13]: import re

In [14]: sentence = '  hello  apple   \n  \r   \t '

In [15]: pattern = re.compile(r'\s+')

In [16]: sentence = re.sub(pattern, '', sentence)

In [17]: print sentence
helloapple

使用str.translate()

In [78]: sentence = '  hello  apple     \n\r \n\r'

In [79]: print sentence
  hello  apple     
 
In [80]: print sentence.translate(None, ' \n\t\r')
helloapple

只去除左边的空白字符

使用str.lstrip()

In [29]: sentence = '  hello  apple  '

In [30]: sentence.lstrip()
Out[30]: 'hello  apple  '

使用正则

In [35]: import re

In [36]: sentence = '  hello  apple  '

In [37]: sentence = re.sub(r"^\s+", "", sentence, flags=re.UNICODE)

In [39]: sentence
Out[39]: 'hello  apple  '

只去除右边的空白字符

使用str.rstrip()

In [40]: sentence = '  hello  apple  '

In [41]: sentence.rstrip()
Out[41]: '  hello  apple'

使用正则

 In [43]: import re

In [44]: sentence = '  hello  apple  '

In [45]: sentence = re.sub(r"\s+$", "", sentence, flags=re.UNICODE)

In [46]: sentence
Out[46]: '  hello  apple'

仅去除重复的空白字符

使用正则

 In [66]: import re

In [67]: sentence = '  hello  apple     '

In [68]: sentence = " ".join(re.split("\s+", sentence, flags=re.UNICODE))

In [69]: sentence
Out[69]: ' hello apple '

综上，str.strip()会移除字符串中开头与结束(左右两侧)的空白字符，中间部分的空白字符是不会移除的。 strip方法中可自定义要移除的字符，如下面这个示例，移除的为字符串中两侧的逗号

In [85]: ",1,2,3,".strip(",")
Out[85]: '1,2,3'

strip does a rstrip and lstrip (removes leading and trailing spaces, tabs, returns and form 
feeds, but it does not remove them in the middle of the string).