removing empty lines using java regex

Question

I have an interesting string I want to properly break up into a string array. This string is as follows.

String test="?[32,120],x1y1,[object pieceP1],null]";

Now I have this regular expression to attack this.

String delims = "[?,\\[\\]]";

Now the results of splitting it using this code

String[] tokens = mapString.split(delims);

yields this result

-->
-->
32
120
-->
x1y1
-->
object pieceP1
-->
null

where the arrows are the empty lines.

How can I modify this regular expression so that there are no empty lines?

Thank you greatly in advance.

~ Selcuk

LiuYan 刘研 · Accepted Answer · 2011-05-12 04:19:34Z

2

String delims = "[?,\\[\\]]+"; // []+

see the Greedy quantifiers part in Summary of regular-expression constructs of Pattern

but the leading empty element is still there.

edited May 12, 2011 at 4:19

answered May 12, 2011 at 4:08

LiuYan 刘研

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denis.solonenko · Accepted Answer · 2011-05-12 03:54:57Z

2

You could use Google Guava's Splitter class to facilitate that: http://guava-libraries.googlecode.com/svn/tags/release09/javadoc/com/google/common/base/Splitter.html

Splitter.omitEmptyStrings() should do the work.

answered May 12, 2011 at 3:54

denis.solonenko

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Favonius · Accepted Answer · 2011-05-12 04:05:35Z

1

Try this

public class Regex 
{
    public static void main(String[] args) 
    {
        String []split = "?[32,120],x1y1,[object pieceP1],null]".split("([?,\\[\\]])+");
        for (int i = 0; i < split.length; i++) {
            System.out.println("'"+split[i]+"'");
        }
    }
}

If your test string starts with a delimiter then the index 0 of the array will always be an empty string. You can put a check for it like this if(split[0].length == 0) continue;

>>Output

''
'32'
'120'
'x1y1'
'object pieceP1'
'null'

answered May 12, 2011 at 4:05

Favonius

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