Error upon adding an array to List<String[]>

Question

List<String[]> list = new ArrayList<String[]>();
String str = "a b c";
list.add(str.split(" "));

Basically I want an array of {a, b, c} however this isn't working. Do I have to iterate and load each element instead? How would I do this?

My error output looks like this:

[Ljava.lang.String;@3d4b7453
[Ljava.lang.String;@24c21495

Those aren't errors, those are the string representations of the arrays. — ataylor
– ataylor, Commented Oct 16, 2012 at 16:08
Not sure I am following, if you want array {a,b,c} what is the List for? Are you trying deliberately to populate the list with arrays? — amit
– amit, Commented Oct 16, 2012 at 16:08
@meiryo The code will work fine, and will give you a list with the specified array in it.. What did you expected? — Rohit Jain
– Rohit Jain, Commented Oct 16, 2012 at 16:10
@amit I have a bunch of strings with stuff like a b c. I want to loop through them and store it all in a list of arrays. — meiryo
– meiryo, Commented Oct 16, 2012 at 16:10

Brian · Accepted Answer · 2012-10-16 16:10:06Z

4

Your code works fine, but it looks like you're printing the wrong thing. Do this instead:

for (String[] strs : list) {
    System.out.println(Arrays.toString(strs));
}

Printing just an array will give you output like what you're seeing.

answered Oct 16, 2012 at 16:10

Brian

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2 Comments

meiryo Over a year ago

Thanks. How do I reference the first element of an array in a list?

Eng.Fouad Over a year ago

@meiryo list.get(0)[0] gives you the first element of the first array in the list.

Peter Lawrey · Accepted Answer · 2012-10-16 16:10:50Z

1

Try

List<String[]> list = new ArrayList<String[]>();
String str = "a b c";
list.add(str.split(" "));
System.out.println(Arrays.toString(list.get(0)));

answered Oct 16, 2012 at 16:10

Peter Lawrey

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Comments

Rohit Jain · Accepted Answer · 2012-10-16 16:12:10Z

1

I think you want to print this way: -

    List<String[]> list = new ArrayList<String[]>();
    String str = "a b c";
    list.add(str.split(" "));

    System.out.println(Arrays.toString(list.get(0)));

This prints: - [a, b, c]

answered Oct 16, 2012 at 16:12

Rohit Jain

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Comments

Eng.Fouad · Accepted Answer · 2012-10-16 16:15:17Z

1

You could use Arrays.toString() to print elements of an array,

System.out.println(Arrays.toString(list.get(0)));

or alternatively iterate over them:

for(String s : list.get(0)) System.out.println(s);

edited Oct 16, 2012 at 16:15

answered Oct 16, 2012 at 16:10

Eng.Fouad

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Comments

Lo Juego · Accepted Answer · 2012-10-16 16:16:11Z

0

You can use Arrays.asList()

List<String> list = new ArrayList<String>();
String str = "a b c";
list.addAll(Arrays.asList(str.split(" ")));

To print the result is like:

for (int i = 0; i < list.size(); i++) {
        System.out.println(list.get(i));
    }
}

answered Oct 16, 2012 at 16:16

Lo Juego

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