CODEWITHSUNDEEP
javaguava
kevinarpe
kevinarpe

Reputation: 21319

How can I join an array using Google Guava (Java)?

I am trying to join int[] (array of int) using Google Guava's Joiner class.

Example:

int[] array = { 1, 2, 3 };
String s = Joiner.on(", ").join(array);  // not allowed

I checked StackOverflow and Google. There is no "one-liner" in foundation classes to convert int[] to Integer[] or List<Integer>. It always requires a for loop, or your own hand-rolled helper function.

Any advice?

Upvotes: 14

Views: 8785

Answers (3)

Jens Hoffmann
Jens Hoffmann

Reputation: 6801

Ints is a Guava library containing helper functions.

Given int[] array = { 1, 2, 3 } you can use the following:

String s = Joiner.on(", ").join(Ints.asList(array));

Or more succinctly:

String s = Ints.join(", ", array);

Upvotes: 32

dmitriykovalev
dmitriykovalev

Reputation: 644

Static method Ints.join(String separator, int... array) should also work.

Upvotes: 23

John B
John B

Reputation: 32969

The reason they did not add a signature for join(int[]) is that then they would have had to add one for each primitive type. Since autoboxing works automatically to convert Integer to int you can pass in an Integer[].

As you said, use Ints.asList(array) to get an Iterable<Integer> from your int[].

Upvotes: 0

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