Best way to convert numeric array to CSV string?

Question

If I have a String[] (assume no commas) I can produce a CSV row simply. Eg,

String[] header = {"header0", "header1", "header2"};
String joined = String.join(",", header);

What's the nice way to do the equivalent with say int[] vals01 = {0, 1, 2}; ? (I consider using Arrays.toString and slicing off the ends to be ugly.)

Answer 1

This can be done with the Streams API in a one-liner:

Arrays.stream(new int[] {0, 1, 2}).mapToObj(String::valueOf).collect(joining(","));

(assuming import static java.util.stream.Collectors.joining )

Answer 2

Consider using the new (Java 8) StringJoiner .

For a String[] :

String[] header = {"header0", "header1", "header2"};
StringJoiner joiner = new StringJoiner(",");
Arrays.stream(header).forEach(joiner::add);
String joined = joiner.toString();

For the case of int[] :

int[] ints = {1, 2, 3};
StringJoiner joiner = new StringJoiner(",");
Arrays.stream(ints).forEach(i -> joiner.add(Integer.toString(i)));
String joined = joiner.toString();
System.out.println(joined);