regular expression extract string between two strings

Question

I am trying to extract strings using regexp. For example in the following string:

select DESCENDANTS([Customer].[Yearly Income],,LEAVES) on axis(0),
       DESCENDANTS([Sales Territory].[Sales Territory],,LEAVES) on axis(1),
       DESCENDANTS([Customer].[Total Children],,LEAVES) on axis(2)
  from [Adventure Works]
 where [Measures].[Internet Sales Amount]

I want to extract the substring between every pair of "DESCENDANTS(" and ",,".

So the result in this case would be: [Customer].[Yearly Income], [Sales Territory].[Sales Territory], [Customer].[Total Children]

Any help is appreciated. Thanks in advance.

mikej · Accepted Answer · 2010-08-31 22:25:53Z

4

If you have your text in a string called query you can do:

query.scan(/DESCENDANTS\((.+),,/).flatten
=> ["[Customer].[Yearly Income]", "[Sales Territory].[Sales Territory]",
"[Customer].[Total Children]"]

Some notes:

\( matches the literal open bracket
(.+) remembers the characters between the open bracket and the two commas as a capture
If the regexp contains captures () then scan will return an array of arrays of the captured parts for each match. In this case there is only 1 capture per match so flatten can be used to return a single array of all the matches we are interested in.

edited Aug 31, 2010 at 22:25

answered Aug 31, 2010 at 22:20

mikej

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Comments

Aillyn · Accepted Answer · 2010-08-31 22:21:26Z

1

/DESCENDANTS\(([^,]+),,/

See it on rubular

answered Aug 31, 2010 at 22:21

Aillyn

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1 Comment

glenn jackman Over a year ago

that will exclude descendants that happen to contain commas.

glenn jackman · Accepted Answer · 2010-09-01 11:08:17Z

0

Here's an uglier variation that uses split: split on "DESCENDANTS(" and ",,", and take every other substring:

s.split(/DESCENDANTS\(|,,/).each_with_index.inject([]) {|m,(e,i)| m << e if i.odd?; m}

answered Sep 1, 2010 at 11:08

glenn jackman

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Comments

zzzhc · Accepted Answer · 2010-09-01 13:05:43Z

0

.+? is more safe, it works correctly if SQL is in one line.

query.scan(/DESCENDANTS\((.+?),,/).flatten

answered Sep 1, 2010 at 13:05

zzzhc

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