Python正则表达式查找双引号外的嵌套括号

Question

我有一个输入字符串，里面有括号，外面有双引号。这些括号可以嵌套。我想去掉只有在双引号外才有括号的字符串。

我尝试了这个正则表达式r'\((?:[^)(]|\((?:[^)(]|\([^)(]*\))*\))*\)'这将获取包含在圆括号内的所有内容，无论双引号内外。

    import re
    input_string = '''"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is(strip this (strip this also as it is outside double quotes))'''
    result = re.sub(r'\((?:[^)(]|\((?:[^)(]|\([^)(]*\))*\))*\)','', input_string)
    print result

我得到的实际输出是：

'"Hello World "  anything outside round brackets should remain as is'

我预计产出为：

'"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is'

Answer 1

使用regex而不是re，您可以使用

"[^"]+"(*SKIP)(*FAIL) # ignore anything between double quotes
|                     # or
\(
    (?:[^()]*|(?R))+  # match nested parentheses
\)

查看regex101上的演示。通用域名格式。

import regex as re

data = """"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is(strip this (strip this also as it is outside double quotes))"""

rx = re.compile(r'''
    "[^"]+"(*SKIP)(*FAIL)
    |
    \(
        (?:[^()]*|(?R))+
    \)''', re.VERBOSE)

data = rx.sub("", data)
print(data)

顺从的

"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is

Answer 2

如果你的括号是平衡的（借助这个答案）：

import re
input_string = '''"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is(strip this (strip this also as it is outside double quotes) xxx) Also remain this (String this)'''

def strip_parentheses(g):
    n = 1  # run at least once
    while n:
        g, n = re.subn(r'\([^()]*\)', '', g)  # remove non-nested/flat balanced parts
    return g

s = re.sub(r'".*?"|([^"]*)', lambda g: strip_parentheses(g.group(1)) if g.group(1) else g.group(), input_string)

print(s)

印刷品：

"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is Also remain this 

编辑运行一些测试用例：

import re
input_string = '''"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is(strip this (strip this also as it is outside double quotes) xxx) Also remain this ((String this))'''

test_cases = ['Normal string (strip this)',
'"Normal string (dont strip this)"',
'"Normal string (dont strip this)" but (strip this)',
'"Normal string (dont strip this)" but (strip this) and (strip this)',
'"Normal string (dont strip this)" but (strip this) and (strip this) but "dont strip (this)"',
'"Normal string (dont strip this)" but ((strip this) and this) and (strip (strip this))',
'"Normal string (dont strip this)" but ((strip this) but "remain this (xxx)") ',
]

def strip_parentheses(g):
    n = 1  # run at least once
    while n:
        g, n = re.subn(r'\([^()]*\)', '', g)  # remove non-nested/flat balanced parts
    return g

def my_strip(s):
    return re.sub(r'".*?"|([^"]*)', lambda g: strip_parentheses(g.group(1)) if g.group(1) else g.group(), s)

for test in test_cases:
    print(test)
    print(my_strip(test))
    print()

印刷品：

Normal string (strip this)
Normal string 

"Normal string (dont strip this)"
"Normal string (dont strip this)"

"Normal string (dont strip this)" but (strip this)
"Normal string (dont strip this)" but 

"Normal string (dont strip this)" but (strip this) and (strip this)
"Normal string (dont strip this)" but  and 

"Normal string (dont strip this)" but (strip this) and (strip this) but "dont strip (this)"
"Normal string (dont strip this)" but  and  but "dont strip (this)"

"Normal string (dont strip this)" but ((strip this) and this) and (strip (strip this))
"Normal string (dont strip this)" but  and 

"Normal string (dont strip this)" but ((strip this) but "remain this (xxx)") 
"Normal string (dont strip this)" but ( but "remain this (xxx)") 

编辑：删除所有（），即使其中包含引号字符串：

import re
input_string = '''"Hello World (Don't want to strip this (also not this))"  anything outside round brackets should remain as is(strip this (strip this also as it is outside double quotes) xxx) Also remain this ((String this))'''

test_cases = ['"Normal string (dont strip this)" but (strip this) and (strip this) but "dont strip (this)"',
'"Normal string (dont strip this)" but ((strip this) and this) and (strip (strip this))',
'"Normal string (dont strip this)" but ((strip this) but "remain this (xxx)") ',
]

def strip_parentheses(g):
    n = 1  # run at least once
    while n:
        g, n = re.subn(r'\([^()]*\)', '', g)  # remove non-nested/flat balanced parts
    return g

def my_strip(s):
    s = re.sub(r'".*?"|([^"]*)', lambda g: strip_parentheses(g.group(1)) if g.group(1) else g.group(), s)
    return re.sub(r'".*?"|(\(.*\))', lambda g: '' if g.group(1) else g.group(), s)

for test in test_cases:
    print(test)
    print(my_strip(test))
    print()

印刷品：

"Normal string (dont strip this)" but (strip this) and (strip this) but "dont strip (this)"
"Normal string (dont strip this)" but  and  but "dont strip (this)"

"Normal string (dont strip this)" but ((strip this) and this) and (strip (strip this))
"Normal string (dont strip this)" but  and 

"Normal string (dont strip this)" but ((strip this) but "remain this (xxx)") 
"Normal string (dont strip this)" but