Splitting a csv file with quotes as text-delimiter using String.split()

Question

I have a comma separated file with many lines similar to one below.

Sachin,,M,"Maths,Science,English",Need to improve in these subjects. 

Quotes is used to escape the delimiter comma used to represent multiple values.

Now how do I split the above value on the comma delimiter using String.split() if at all its possible?

Answer 1

public static void main(String[] args) {     String s = "Sachin,,M,\"Maths,Science,English\",Need to improve in these subjects.";     String[] splitted = s.split(",(?=([^\"]*\"[^\"]*\")*[^\"]*$)");     System.out.println(Arrays.toString(splitted)); } 

Output:

[Sachin, , M, "Maths,Science,English", Need to improve in these subjects.] 

Answer 2

As your problem/requirements are not all that complex a custom method can be utilized that performs over 20 times faster and produces the same results. This is variable based on the data size and number of rows parsed, and for more complicated problems using regular expressions is a must.

import java.util.Arrays; import java.util.ArrayList; public class SplitTest {  public static void main(String[] args) {      String s = "Sachin,,M,\"Maths,Science,English\",Need to improve in these subjects.";     String[] splitted = null;   //Measure Regular Expression     long startTime = System.nanoTime();     for(int i=0; i<10; i++)     splitted = s.split(",(?=([^\"]*\"[^\"]*\")*[^\"]*$)");     long endTime =   System.nanoTime();      System.out.println("Took: " + (endTime-startTime));     System.out.println(Arrays.toString(splitted));     System.out.println("");       ArrayList<String> sw = null;          //Measure Custom Method             startTime = System.nanoTime();     for(int i=0; i<10; i++)     sw = customSplitSpecific(s);     endTime =   System.nanoTime();      System.out.println("Took: " + (endTime-startTime));     System.out.println(sw);          }  public static ArrayList<String> customSplitSpecific(String s) {     ArrayList<String> words = new ArrayList<String>();     boolean notInsideComma = true;     int start =0, end=0;     for(int i=0; i<s.length()-1; i++)     {         if(s.charAt(i)==',' && notInsideComma)         {             words.add(s.substring(start,i));             start = i+1;                         }            else if(s.charAt(i)=='"')         notInsideComma=!notInsideComma;     }     words.add(s.substring(start));     return words; }    

}

On my own computer this produces:

Took: 6651100 [Sachin, , M, "Maths,Science,English", Need to improve in these subjects.]  Took: 224179 [Sachin, , M, "Maths,Science,English", Need to improve in these subjects.]