Question

while something:
     do something;
     do somethingelse;
     do thelastthing;
continue with other statements..

我正在尝试创建一个仅与while循环中的最后一个语句匹配的正则表达式。我该怎么做呢？

Answer 1

您应该提供更多信息以获得更清晰的答案。为什么不用变量控制循环，让我们说“c”，将它用作“进入/不进入”变量？例如：

c = 0
while c == 0:
if thisistrue:
    c = 1
else:
    dosomething

Answer 2

如your previous question中所述，您可以使用

捕获while循环的缩进级别

^([ \t]*)  while\b

然后将每一行与相同的缩进级别\1 加上匹配至少一个空格。

\n\1  [ \t]+  (?P<last_statement>.*)

<强>代码

import re

while_loop = re.compile(r'''
            #while statement (group 1 captures the indentation)
            ^([ \t]*)  while\b  .*  $

            #code
            (?:
                #comments with any indentation
                (?:
                    \s*?
                    \n  [ \t]*  [#].* 
                )*

                #Optional else lines
                (?:
                    \s*?
                    \n\1  else  [ \t]*  .*  $
                )?

                #following lines with more indentation
                \s*?
                \n\1  [ \t]+  (?P<last_statement>.*)
            )*

            \n?
''', re.MULTILINE | re.VERBOSE)


test_str = r'''
            while something:
                do something;
                do somethingelse;
                do thelastthing;
            continue with other statements..
'''


# Loop matches
m = 0
for match in while_loop.finditer(test_str):
    m += 1
    print( 'Match #%s [%s:%s]\nLast statement [%s:%s]:\t"%s"' 
        %(m, match.start(), match.end(), match.start("last_statement"),
        match.end("last_statement"), match.group("last_statement")))

if m == 0:
    print("NO MATCH")

<强>输出

Match #1 [1:91]
Last statement [74:90]: "do thelastthing;"

ideone demo

查找序列正则表达式的最后一次出现

2 个答案: