如何 Grep 在查找中搜索两次出现的字符

Question

I seem to have to perpetually relearn Regex & Grep syntax every time I need something advanced. This time, even with BBEDIT's pattern playground, I can't work this one out.

I need to do a multi-line search for the occurrence of two literal asterisks anywhere in the text between a pair of tags in a plist/XML file.

I can successfully construct a lookbetween so:

(?s)(?<=<array>).*?(?=</array>)

I try to limit that to only match occurrences in which two asterisks appear between tags:

(?s)(?<=<array>).*?[*]{2}.*?(?=</array>)
(?s)(?<=<array>).+[*]{2}.+(?=</array>)
(?s)(?<=<array>).+?[*]{2}.+?(?=</array>)

But they find nought. And when I remove the {2} I realize I'm not even constructing it right to find occurrences of one asterisk. I tried escaping the character /* and [/*] but to no avail.

How can i match any occurrence of blah blah * blah blah * blah blah?

Answer 1

[*]{2} means the two asterisks must be consecutive.

(.*[*]){2} is what you're looking for - it contains two asterisks, with anything in between them.

But we also need to make sure the regex is only testing one tag closure at the same time, so instead of .* , we need to use ((?.<\/array>).)* to make sure it won't consume the end tag </array> while matching .*

The regex can be written as:

(?s)(?<=<array>)(?:((?!<\/array>).)*?[*]){2}(?1)*

See the test result here

Answer 2

Use

(?s)(?<=<array>)(?:(?:(?!<\/?array>)[^*])*[*]){2}.*?(?=</array>)

See proof .

Explanation

NODE	EXPLANATION
(?s)	set flags for this block (with. matching \n) (case-sensitive) (with ^ and $ matching normally) (matching whitespace and # normally)
(?<=	look behind to see if there is:
<array>	'<array>'
)	end of look-behind
(?:	group, but do not capture (2 times):
(?:	group, but do not capture (0 or more times (matching the most amount possible)):
(?!	look ahead to see if there is not:
</?array>	</array> or <array>
)	end of look-ahead
[^*]	any character except: '*'
)*	end of grouping
[*]	any character of: '*'
){2}	end of grouping
.*?	any character (0 or more times (matching the least amount possible))
(?=	look ahead to see if there is:
</array>	'</array>'
)	end of look-ahead