我有一个这样的字符串:
this is "a test"
我试图在Python中写一些东西,通过空格分割它,同时忽略引号中的空格。我想要的结果是:
['this', 'is', 'a test']
PS,我知道你会问“如果引号中有引号会发生什么,在我的应用程序中,这永远不会发生。
我有一个这样的字符串:
this is "a test"
我试图在Python中写一些东西,通过空格分割它,同时忽略引号中的空格。我想要的结果是:
['this', 'is', 'a test']
PS,我知道你会问“如果引号中有引号会发生什么,在我的应用程序中,这永远不会发生。
当前回答
你需要从内置的shlex模块中分离。
>>> import shlex
>>> shlex.split('this is "a test"')
['this', 'is', 'a test']
这应该是你想要的效果。
如果你想保留引号,那么你可以传递posix=False kwarg。
>>> shlex.split('this is "a test"', posix=False)
['this', 'is', '"a test"']
其他回答
你需要从内置的shlex模块中分离。
>>> import shlex
>>> shlex.split('this is "a test"')
['this', 'is', 'a test']
这应该是你想要的效果。
如果你想保留引号,那么你可以传递posix=False kwarg。
>>> shlex.split('this is "a test"', posix=False)
['this', 'is', '"a test"']
不同答案的速度测试:
import re
import shlex
import csv
line = 'this is "a test"'
%timeit [p for p in re.split("( |\\\".*?\\\"|'.*?')", line) if p.strip()]
100000 loops, best of 3: 5.17 µs per loop
%timeit re.findall(r'[^"\s]\S*|".+?"', line)
100000 loops, best of 3: 2.88 µs per loop
%timeit list(csv.reader([line], delimiter=" "))
The slowest run took 9.62 times longer than the fastest. This could mean that an intermediate result is being cached.
100000 loops, best of 3: 2.4 µs per loop
%timeit shlex.split(line)
10000 loops, best of 3: 50.2 µs per loop
如果你不关心子字符串
>>> 'a short sized string with spaces '.split()
性能:
>>> s = " ('a short sized string with spaces '*100).split() "
>>> t = timeit.Timer(stmt=s)
>>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
171.39 usec/pass
或者字符串模块
>>> from string import split as stringsplit;
>>> stringsplit('a short sized string with spaces '*100)
性能:String模块的性能似乎比字符串方法更好
>>> s = "stringsplit('a short sized string with spaces '*100)"
>>> t = timeit.Timer(s, "from string import split as stringsplit")
>>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
154.88 usec/pass
或者你可以使用RE引擎
>>> from re import split as resplit
>>> regex = '\s+'
>>> medstring = 'a short sized string with spaces '*100
>>> resplit(regex, medstring)
性能
>>> s = "resplit(regex, medstring)"
>>> t = timeit.Timer(s, "from re import split as resplit; regex='\s+'; medstring='a short sized string with spaces '*100")
>>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
540.21 usec/pass
对于非常长的字符串,您不应该将整个字符串加载到内存中,而是将行分开或使用迭代循环
我建议:
测试字符串:
s = 'abc "ad" \'fg\' "kk\'rdt\'" zzz"34"zzz "" \'\''
也要捕捉""和":
import re
re.findall(r'"[^"]*"|\'[^\']*\'|[^"\'\s]+',s)
结果:
['abc', '"ad"', "'fg'", '"kk\'rdt\'"', 'zzz', '"34"', 'zzz', '""', "''"]
忽略空的""和":
import re
re.findall(r'"[^"]+"|\'[^\']+\'|[^"\'\s]+',s)
结果:
['abc', '"ad"', "'fg'", '"kk\'rdt\'"', 'zzz', '"34"', 'zzz']
要解决某些Python 2版本中的unicode问题,我建议:
from shlex import split as _split
split = lambda a: [b.decode('utf-8') for b in _split(a.encode('utf-8'))]