im trying to randomly select elements from 3 array of Strings?

Question

I'm trying to randomly select elements from 3 array of Strings?

private static String[] one   ={"dog, cat"};
private static String[] two   ={"ate, ran"};
private static String[] three ={"away, some}"

Random words = new Random();
int index=words.nextInt(one.length+two.length+three.length);

System.out.println(one[index]);

What do you think `words.nextInt(one.length+two.length+three.length);` does or should do and why do you think so? — Pshemo, Dec 15 '15 at 03:25
Are you trying to pick one random element from any of the three arrays or one random element from each of the three arrays? — Daniel Centore, Dec 15 '15 at 03:55

score 1 · Answer 1 · answered Dec 15 '15 at 03:41

The problem with the program is that you're getting a random number between 0 and 6 and then using this random number as an index to get a value from only the first array. There are two problems here,

one[index] will cause an arrayindexoutofboundsexception in some cases because the max index for one is 1 when index can also be 2,3,4, or 5.
also, the objective is to get a random element from THREE arrays of strings, not just one

My suggestion is getting a random number between one and three (inclusive) to choose one of the string arrays, then find a random number between 0 and the chosen array's length. And assign that to the index of the chosen array.

score 0 · Answer 2 · edited May 23 '17 at 12:23

A two step approach is probably best:

Combine all your arrays into one larger array. This SO thread demonstrates several ways to accomplish this. For example, try this method (from here):

public String[] concat(String[] a, String[] b) {
    int aLen = a.length;
    int bLen = b.length;
    String[] c= new String[aLen + bLen];
    System.arraycopy(a, 0, c, 0, aLen);
    System.arraycopy(b, 0, c, aLen, bLen);
    return c;
}

// use it like this
String[] combined = concat(concat(one, two), three);

Pick a random element from the combined array, and print it:

int index = r.nextInt(combined.length);
System.out.println(combined[index]);

im trying to randomly select elements from 3 array of Strings?

2 Answers2