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
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
其他回答
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
要保留引号,使用这个函数:
def getArgs(s):
args = []
cur = ''
inQuotes = 0
for char in s.strip():
if char == ' ' and not inQuotes:
args.append(cur)
cur = ''
elif char == '"' and not inQuotes:
inQuotes = 1
cur += char
elif char == '"' and inQuotes:
inQuotes = 0
cur += char
else:
cur += char
args.append(cur)
return args
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
试试这个:
def adamsplit(s):
result = []
inquotes = False
for substring in s.split('"'):
if not inquotes:
result.extend(substring.split())
else:
result.append(substring)
inquotes = not inquotes
return result
一些测试字符串:
'This is "a test"' -> ['This', 'is', 'a test']
'"This is \'a test\'"' -> ["This is 'a test'"]
由于性能原因,re似乎更快。下面是我的解决方案,使用最小贪婪操作符,保留外部引号:
re.findall("(?:\".*?\"|\S)+", s)
结果:
['this', 'is', '"a test"']
它将像aaa“bla blub”bbb这样的结构放在一起,因为这些标记没有被空格分隔。如果字符串包含转义字符,你可以这样匹配:
>>> a = "She said \"He said, \\\"My name is Mark.\\\"\""
>>> a
'She said "He said, \\"My name is Mark.\\""'
>>> for i in re.findall("(?:\".*?[^\\\\]\"|\S)+", a): print(i)
...
She
said
"He said, \"My name is Mark.\""
请注意,这也通过模式的\S部分来匹配空字符串“”。