What's the most elegant/concise way of printing all strings in a list into a single string?

Question

Is there an elegant way (elegant meaning without an iterator or a loop) to print every member of Java's List<Sting> object into a comma-separated string?

E.g., Java's version of Perl's my $allElementsString = join(",", @myStrings);

I checked List interface and didn't find anything promising (my best guess was to use toArray and then Array's toString?)

`List.toString()` would return a comma-separated list, but it would include braces on the end. — Louis Wasserman, Oct 08 '13 at 16:30
@zch - probably a closer one is http://stackoverflow.com/questions/63150/whats-the-best-way-to-build-a-string-of-delimited-items-in-java — DVK, Oct 08 '13 at 16:37

score 4 · Answer 1 · answered Oct 08 '13 at 16:30

4

There's nothing in the JDK to do this directly. You can implement your own joiner with StringBuilder or use a 3rd party library like Guava

List<String> string = ...;
String list = Joiner.on(",").join(string);

answered Oct 08 '13 at 16:30

Sotirios Delimanolis

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score 1 · Answer 2 · answered Oct 08 '13 at 16:30

1

if it is a list of Strings then simply print it :

System.out.println(yourList);

If it is a list of custom objects then make sure you have overriden toString method in your custom class to print the List objects properly.

answered Oct 08 '13 at 16:30

Juned Ahsan

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score 1 · Answer 3 · answered Oct 08 '13 at 16:32

I think most people use Apache Commons' StringUtils:

List<String> yourStrings = /* something */;
String commaSeperated = StringUtils.join(yourStrings, ',');

The Apache Commons libraries are extremely convenient. I'd recommend looking at them (or Google's Guava).

score 1 · Answer 4 · answered Oct 08 '13 at 16:32

1

Something like this:

List<String> list = new ArrayList<>();
list.add("1");
list.add("2");
list.add("3");
String result = list.toString().substring(1, list.toString().length() - 1);
System.out.println(result);

OUTPUT:

1, 2, 3

answered Oct 08 '13 at 16:32

Eng.Fouad

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Writing it as a one-liner does not pay off calling `list.toString()` twice, especially in real-life code where the list might be large. Having one more line of code for a local variable is not that bad. – Holger Oct 08 '13 at 17:26

score 0 · Answer 5 · answered Oct 08 '13 at 16:30

0

Not in the JDK but there is guava and other utility libraries also offer similar solutions.

answered Oct 08 '13 at 16:30

Pyranja

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score 0 · Answer 6 · answered Oct 08 '13 at 16:30

0

Nope. Any toString method you might apply to List or the Array wouldn't be formatted in any meaningful way.

answered Oct 08 '13 at 16:30

Kyle Falconer

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score 0 · Answer 7 · answered Oct 08 '13 at 16:31

0

Either use Guava as already pointed out, or Apache Common's StringUtils:

StringUtils.join( list, ",");

answered Oct 08 '13 at 16:31

Thomas

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score 0 · Answer 8 · edited May 23 '17 at 12:28

0

See Best way to concatenate List of String objects?

Quoted, Use one of the the StringUtils.join methods in Apache Commons Lang.

import org.apache.commons.lang3.StringUtils;

String result = StringUtils.join(list, ", ");

edited May 23 '17 at 12:28

Community

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answered Oct 08 '13 at 16:32

ChuckCottrill

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score 0 · Answer 9 · answered Oct 08 '13 at 16:32

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you can use org.apache.commons.lang.StringUtils.join method

answered Oct 08 '13 at 16:32

stinepike

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What's the most elegant/concise way of printing all strings in a list into a single string?

9 Answers9