不带高级正则表达式

Question

Hi regular expression experts,

I have the following text

<[~UNKNOWN:a-z\.]> <[~UNKNOWN:A-Z\-0-9]> <[~UNKNOWN:A-Z\]a-z]

And the following reg expr

\[\~[^\[\~\]]*\]

It works fine for the 1st and 2nd group in the text but not for the 3rd one.

The 1st group is

[~UNKNOWN:a-z\.]

The 2nd is

[~UNKNOWN:A-Z\-0-9]

and the 3rd one is

[~UNKNOWN:A-Z\]a-z]

However the reg exp finds the following text

[~UNKNOWN:A-Z\]

I understand why and I know that I have to add the following rule to the reg exp:
starting with '[' and '~' characters and ending with ']' UNLESS there is a '\\' in front of ']'. So I should add a NOT expression but not sure how.

Could anybody please help?

Thanks,
V.

Answer 1

Why not simply:

<([^>]+)>?

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Regex Demo

Answer 2

This should work (first line pattern, second line your pattern (ignore whitespace), third line my changes):

\[\~(?:[^\[\~\]]|(?<=\\)\])*(?<!\\)\]
\[\~   [^\[\~\]]           *       \]
    (?:         |(?<=\\)\]) (?<!\\)

Your regex:

\[\~             # Literal characters [~
[^               # Character group, NONE of the following:
    \[\~\]       # [ or ~ or ]
]*               # 0 or more of this character group
\]               # Followed by ]

Your pattern in words: [~ , everything in between, up to the next ] , as long as there is no [ or ~ or ] in there.

My pattern , only relevant changes explained:

\[\~             
(?:              # Non capturing group
    [^\[\~\]]    
    |            # OR
    (?<=\\)\]    # ], preceded by \
)*               
(?<!\\)\]         # ], not preceded by \

In words: Same as yours, plus ] may be contained if it is preceded by \\ , and the closing ] may not be preceded by \\