java - split string using regular expression

Question

I need to split a string where there's a comma, but it depends where the comma is placed.

As an example

consider the following:

C=75,user_is_active(A,B),user_is_using_app(A,B),D=78

I'd like the String.split() function to separate them like this:

C=75 

user_is_active(A,B) 

user_using_app(A,B)

D=78

I can only think of one thing but I'm not sure how it'd be expressed in regex.

The characters/words within the brackets are always capital. In other words, there won't be a situation where I will have user_is_active(a,b).

Is there's a way to do this?

Tim Pietzcker · Accepted Answer · 2011-03-19 16:18:21Z

12

If you don't have more than one level of parentheses, you could do a split on a comma that isn't followed by a closing ) before an opening (:

String[] splitArray = subjectString.split(
    "(?x),   # Verbose regex: Match a comma\n" +
    "(?!     # unless it's followed by...\n" +
    " [^(]*  # any number of characters except (\n" +
    " \\)    # and a )\n" +
    ")       # end of lookahead assertion");

Your proposed rule would translate as

String[] splitArray = subjectString.split(
    "(?x),        # Verbose regex: Match a comma\n" +
    "(?<!\\p{Lu}) # unless it's preceded by an uppercase letter\n" +
    "(?!\\p{Lu})  # or followed by an uppercase letter");

but then you would miss a split in a text like

Org=NASA,Craft=Shuttle

edited Mar 19, 2011 at 16:18

answered Mar 19, 2011 at 16:12

Tim Pietzcker

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3 Comments

kkudi Over a year ago

this works prefect! I dont think I will have more than one level parentheses! thanks! :D

ridgerunner Over a year ago

+1 And if the (A,B) construct will only ever have one comma inside, you can speed this up dramatically by adding a comma to the [^(]* expression i.e. [^(,]*.

kkudi Over a year ago

in my case I could have something(A,B,C) so it wouldn't apply but it's good to know! thanks!

Pierre · Accepted Answer · 2011-03-19 16:15:47Z

0

consider using a parser generator for parsing this kind of query. E.g: javacc or antlr

answered Mar 19, 2011 at 16:15

Pierre

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Comments

Alberto · Accepted Answer · 2011-03-19 16:24:23Z

0

As an alternative, if you need more than one level of parentheses, you can create a little string parser for parsing the string character by character.

answered Mar 19, 2011 at 16:24

Alberto

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