Java - Splitting data into a 2D array

Question

I have a String of data called purchaseData which is separated into into lines with "\n" and into fields with "," (in CSV format).

How could I make a 2D string array so that the array contains arrays with each of the fields in. So for String[i][j], i would be the line value (position of row) and j would be the position of the field within the selected array of data (the row).

Have you tried anything? What I would recommend is an embedded loop (outer gets the next line inner gets the fields from that line). I can give you the code but I want to know what you've tried so far. — twain249
– twain249, Commented Mar 12, 2012 at 19:19

anubhava · Accepted Answer · 2012-03-12 20:03:14Z

2

You can use String#split to create 2D array like this:

String str = "a,b,c,d,e,f\ng,h,i,j,k,l\nm,n,o,p,q,r";
String[] arr = str.split("\n");
String[][] csv = new String[arr.length][];
for(int r=0; r<arr.length; r++)
    csv[r] = arr[r].split(",");

Update: Since Max commented (and I agree) that my original answer won't work with RFC 4180 type CSV here I am posting an update to parse those complex CSV data like in my example below:

String str =
  "m,n,o,\"p\nx\",q,r\n\"abc,123\",\"45,12\",\"a,aa\",\"b,bb\",\"c,cc\",\"fo\no,bar\"";

String[] arr = str.split("\n\\s*(?=([^\"]*\"[^\"]*\")*[^\"]*$)");
String[][] csv = new String[arr.length][];
for(int r=0; r<arr.length; r++)
    csv[r] = arr[r].split(",\\s*(?=([^\"]*\"[^\"]*\")*[^\"]*$)");

Testing:

for(int r=0; r<csv.length; r++)
    System.out.println(Arrays.toString(csv[r]));

OUTPUT:

[m, n, o, "p
x", q, r]
["abc,123", "45,12", "a,aa", "b,bb", "c,cc", "fo
o,bar"]

edited Mar 12, 2012 at 20:03

answered Mar 12, 2012 at 19:27

anubhava

790k67 gold badges603 silver badges671 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

bezmax Over a year ago

+1, however if the format in question is RFC 4180 type CSV, then only a proper parser will be able to parse it. For example, this is proper CSV with 3 columns: "abc,123","2345\n12","a,aa""b,bb""c,cc"

anubhava Over a year ago

Fully agree @Max that only a proper parser can work with those kind of CSV data.

anubhava Over a year ago

@Max: I have posted an update to my answer which should work with RFC 4180 type CSV as well.

aviad · Accepted Answer · 2012-03-12 20:59:13Z

1

    String str = "YOUR_VERY_LONG_STRING";
    String[] lines = str.split("\n");
    String[][] linesCsv = new String[lines.length][];

    for (int i=0; i<lines.length; i++) {
        linesCsv[i] = lines[i].split(",");
    }

edited Mar 12, 2012 at 20:59

answered Mar 12, 2012 at 19:28

aviad

8,2789 gold badges55 silver badges100 bronze badges

Collectives™ on Stack Overflow

Java - Splitting data into a 2D array

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related