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Can some one decode what these regex do?

Posted on 2006-07-22
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Last Modified: 2010-03-31
I am debugging a piece of code and have a following scenario

private String REGEXP_VARIABLE_EXPANSION = "\\$\\{([\\w\\.?]*)\\}";

// How we test for booleans
private String REGEXP_BOOLEAN_VALUE = "True|T|Yes|Y";

If someone can give me an example string that will be great.  I know reverse engineering is crazy but what to do?

I am not a regex person.  But I have to work with a code.

Thanx in advance

slick

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Question by:slickdeals
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9 Comments
 
LVL 37

Accepted Solution

by:
Harisha M G earned 168 total points
ID: 17161560
"\\$\\{([\\w\\.?]*)\\}"

By de-escaping (?) it, the regex becomes:

\$\{([\w\.?]*)\}

So, it matches any string that has initially a $ sign, then { and a character, then any no of characters, again }

For ex,

${hello}

would match, but

${ hello}, ${.hello} etc won't match.


And the second one matches only True, T, Yes or Y
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LVL 26

Expert Comment

by:ksivananth
ID: 17162023
I think, it is

${Combination of alpha numeric chars with dots}
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Assisted Solution

by:ksivananth
ksivananth earned 166 total points
ID: 17162034
for e.g.,

"${hello.123.fine} Some Text ${hello1233...} Some more here ${Not Matches.}"

it matches,

${hello.123.fine}
${hello1233...}
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LVL 26

Expert Comment

by:ksivananth
ID: 17162043
I feel, the "?" in the regex is irrelevant
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LVL 86

Assisted Solution

by:CEHJ
CEHJ earned 166 total points
ID: 17162434
>>I feel, the "?" in the regex is irrelevant

True. Of course the regex will also match the empty var:

${}

The other one should probably be named

REGEXP_BOOLEAN_VALUE_TRUE

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LVL 26

Expert Comment

by:ksivananth
ID: 17162457
>>Of course the regex will also match the empty var:

true
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LVL 37

Expert Comment

by:Harisha M G
ID: 17162738
${.hello} matches.. I was thinking of something else..
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