仅当前后有奇数个字符时，正则表达式才匹配

Question

我想将以下字符串的结束引号与开始引号匹配（如果两者位于同一行）。两个字符串可以用空格

或 blank-plus-blank

 + 

.

分隔。

正则表达式引擎：Python

F.i.来自

this is "some string" "; which should match" 234
"and this" + "should also match\"" "\"and this" 
but not this: " " a " + "

我想查看以下匹配项：

• 第 1 行：

  " "

  ，位于

  some string

  和

  ; which...

之间
• 第2行：

  • " + "

    位于

    and this

    和

    should also match\"

  之间

  • " "

    位于

    should also match\"

    和

    \"and this

  之间
• 第 3 行：没有匹配项

所以事实上，我认为最好只匹配组

" "

和

" + "

，如果在组之前和之后有奇数个引号。由于lookbehining/ahead只是固定长度，我没有找到一个好的方法来做到这一点。 我试过了

re.compile(r'(" \+ ")|(" ")(?!;|,)')

但这假设字符串中可能没有分号还有

re.compile(r'"[^"]+")

但这只能找到字符串本身，而不能找到“字符串间”引号。

这就是我上面提到的字符循环解析方法。 我跟踪我们是否在引号内，并且我跟踪引号之间的字符。

Answer 1

data = """\
this is "some string" "; which should match" 234
"and this" + "should also match\"" "\"and this" 
but not this: " " a " + "
"""

def check(line):
    in_quotes = False
    between = "xxxx"

    for c in line:
        if c == '"':
            if not in_quotes and between in (' ', ' + '):
                return True
            between = ""
            in_quotes = not in_quotes
        elif not in_quotes:
            between += c

for line in data.splitlines():
    print(line)
    if check(line):
        print("MATCHES")

输出：

this is "some string" "; which should match" 234
MATCHES
"and this" + "should also match"" ""and this" 
MATCHES
but not this: " " a " + "