Solved

How to split columns with exceptions

Posted on 2008-10-13
5
463 Views
Last Modified: 2012-05-05
Hi,
   Can anyone help me with this problem:

How can I split CSV file in Java (into separate columns), using built-in regex functions (for efficiency), but ignore everything in double quotes? So:

1,2,3,"hello, world!"

will be treated as 4 columns, not 5.
0
Comment
Question by:Envoy2064
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
5 Comments
 
LVL 27

Expert Comment

by:ddrudik
ID: 22705134
If you won't have empty columns you could do something like:

import java.util.regex.Pattern;
import java.util.regex.Matcher;
class Module1{
  public static void main(String[] asd){
  String sourcestring = "source string to match with pattern";
  Pattern re = Pattern.compile("""[^""]*""|[^,]+");
  Matcher m = re.matcher(sourcestring);
    if(m.find()){
      for( int groupIdx = 0; groupIdx < m.groupCount(); groupIdx++ ){
        System.out.println( "[" + groupIdx + "] = " + m.group(groupIdx));
      }
    }
  }
}

Open in new window

0
 

Author Comment

by:Envoy2064
ID: 22705155
How about with empty columns?
0
 

Author Comment

by:Envoy2064
ID: 22705173
Please note the emphasis on efficient algorithms that uses as much system-optimized code as possible.
0
 
LVL 27

Accepted Solution

by:
ddrudik earned 250 total points
ID: 22734320
For that requirement (remember that you will need to split the file by line and pass each line to the regex function to get the column values):
import java.util.regex.Pattern;
import java.util.regex.Matcher;
class Module1{
  public static void main(String[] asd){
  String sourcestring = "source string to match with pattern";
  Pattern re = Pattern.compile("""[^""]*""|[^,]+|(?<=,)(?=,)|^(?=,)|(?<=,)$");
  Matcher m = re.matcher(sourcestring);
  Int mIdx = 0;
    while (m.find()){
      for( int groupIdx = 0; groupIdx < m.groupCount(); groupIdx++ ){
        System.out.println( "[" + mIdx + "][" + groupIdx + "] = " + m.group(groupIdx));
      }
      mIdx++;
    }
  }
}

Open in new window

0
 
LVL 27

Expert Comment

by:ddrudik
ID: 22779434
Thanks for the question and the points.
0

Featured Post

Is Your DevOps Pipeline Leaking?

Is your CI/CD pipeline a hodge-podge of randomly connected tools? You’ve likely got a tool to fix one problem & then a different tool to fix another, resulting in a cluster of tools with overlapping functionality. Learn how to optimize your pipeline with Gartner's recommendations

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Glassfish admin console not working 1 88
Need a simple RegEx to search for two words 27 124
Tagging and Merging on Branch 1 68
List the words in Notepad++ 16 46
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
In this post we will learn different types of Android Layout and some basics of an Android App.
Video by: Michael
Viewers learn about how to reduce the potential repetitiveness of coding in main by developing methods to perform specific tasks for their program. Additionally, objects are introduced for the purpose of learning how to call methods in Java. Define …
The viewer will learn how to implement Singleton Design Pattern in Java.
Suggested Courses

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question