Java print a whole array, with a " , " sign?

Question

System.out.print("Please select a game: ");
for (String s : gamesArray) {       
    System.out.print(s + ", "); 
}

Output:

Please select a game: spin, tof, Press any key to exit...

The output I am excepting:

Please select a game: spin, tof
Press any key to exit...

Why is it adding another ',' after the last array item? How do I prevent it?

Because as coded now, you are printing `,` after each element, including the last element — Steve Kuo, Jun 24 '13 at 20:07
It's adding another ", " after the last array item because you told it to add one after every array item. — Louis Wasserman, Jun 24 '13 at 20:07
You prevent it by writing your code so that the last comma isn't printed. Several different ways to do this, but none are automatic -- you gotta actually think about it and write the code. — Hot Licks, Jun 24 '13 at 20:09
http://stackoverflow.com/questions/1515437/java-function-for-arrays-like-phps-join has good solutions for this task. — Squeezy, Jun 24 '13 at 21:03

anubhava · Answer 1 · 2013-06-25T14:01:18.303

8

Why not just call Arrays#toString(array):

System.out.print("Please select a game: %s%n", 
                  Arrays.toString(gamesArray).replaceAll("(^\\[)|(\\]$)", ""));

OR to avoid regex:

String tmp = Arrays.toString(gamesArray);
System.out.print("Please select a game: %s%n", tmp.substring(1, tmp.length()-1));

edited Jun 25 '13 at 14:01

answered Jun 24 '13 at 20:10

anubhava

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Because that would print: Please select a game: [spin, tof] rather than without the braces. – ardent Jun 24 '13 at 20:11
@arshajii: Thanks for your comments. I made it `replaceAll("(^\\[)|(\\]$)", "")` to replace only starting and ending square bracket. – anubhava Jun 24 '13 at 20:17
2

I'm glad you made the change (+1). But why not just use `substring`? Regular expressions are overkill when all we want to do is strip away the first and last chars. – arshajii Jun 24 '13 at 20:18
@arshajii: Unfortunately I have already hit the rep limit for today :( In any case yes substring can also be used but then it just cant be done in one call since we'll need to do `str.substring(1, substring.length()-1);` – anubhava Jun 24 '13 at 20:21

score 7 · Answer 2 · answered Jun 24 '13 at 20:07

7

// iterate throght array
for ( int i = 0; i < gamesArray.length; i++ ) {

    // get the element
    String s = gamesArray[i];

    // print it
    System.out.print( s );

    // test if the current element is not the last (array size minus 1)
    if ( i != gamesArray.length - 1 ) {

        // if it is not the last element, print a comma and a space.
        System.out.print( ", " );
    }
}

answered Jun 24 '13 at 20:07

davidbuzatto

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Little excessive with comments, but better. – William Morrison Jun 24 '13 at 20:09
Why did you the variable i isnide the array? [i] ? Sorry for the beginner questions, it just confuses me. – Jony Kale Jun 24 '13 at 20:15

arshajii · Answer 3 · 2013-06-24T20:14:10.860

2

Why is it adding another ' , ' after the last array item?

Because there is nothing special about the last item, you are adding , at the end of every element.

How do I prevent it?

You could try using a regular for-loop and only adding , if the index your on is not the last index of the array. Equivalently, you could add , before each element excluding the first, and you will have the same effect.

int len = gamesArray.length;

if (len > 0)
    System.out.println(gamesArray[0]);

for (int i = 1; i < len; i++)
    System.out.print(", " + gamesArray[i]);

edited Jun 24 '13 at 20:14

answered Jun 24 '13 at 20:07

arshajii

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What does the i inside the [] do? – Jony Kale Jun 24 '13 at 20:50
@JonyKale It accesses the `i`th element of the array. – arshajii Jun 24 '13 at 21:17

score 2 · Answer 4 · answered Jun 24 '13 at 20:22

2

Can you use the Guava library? If yes, it's one line of code:

String result = Joiner.on(", ").join(gamesArray);
System.out.println(result);

answered Jun 24 '13 at 20:22

jlordo

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Apache Commons has a similar join – Steve Kuo Jun 24 '13 at 23:12
And Java8 is getting one too. – Sebastian Redl Jun 25 '13 at 14:13

score 1 · Answer 5 · answered Jun 24 '13 at 20:08

The last comma is there because you're printing a comma after each element.

You can fix this by rewriting the for loop as so:

for(int i=0;i<gameArray.length;i++){
    System.out.print(gameArray[i]);
    if(i!=gameArray.length-1){
        System.out.println(", ");
    }
}

score 1 · Answer 6 · answered Jun 24 '13 at 20:10

1

Another way to handle this (especially good if you know the array will never be empty) is to write the first element before the loop, then have the loop write , <element>.

answered Jun 24 '13 at 20:10

Hot Licks

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Raphaël · Answer 7 · 2013-06-25T21:01:14.720

0

You have to test if there are more elements in your array before printing a "," to avoid having one after the last game name.

final Iterator<String> iterator = Arrays.asList(gamesArray).iterator();
while(iterator.hasNext()) {
    System.out.print(iterator.next());
    if(iterator.hasNext()) {
        System.out.print(", ");
    }
}
System.out.println();

edited Jun 25 '13 at 21:01

answered Jun 24 '13 at 20:17

Raphaël

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Java print a whole array, with a " , " sign?

7 Answers7