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From: Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: What's the best way to make a cross string set?
Date: Thu, 27 Jul 2017 15:49:55 -0400
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On 7/27/2017 3:12 PM, Eric Douglas wrote:
> I have a variable number of lists of values, as in
> ArrayList list1 = new ArrayList()
> ArrayList list2 = new ArrayList()
> list2.add("a")
> list2.add("b")
> list2.add("c")
> list1.add(list2)
> ArrayList list3 = new ArrayList()
> list3.add("1")
> list3.add("2")
> list3.add("3")
> list1.add(list3)
> ArrayList list4 = new ArrayList()
> list4.add("fg")
> list4.add("hj")
> list4.add("kl")
> list1.add(list4)
> 
> Now I want to print only the complete set, as in
> a1fg
> b1fg
> c1fg
> a2fg
> b2fg
> c2fg
> a3fg
> b3fg
> c3fg
> a1hj
> b1hj
> ...

     If by "complete set" you mean "the Cartesian product of all the
lists contained in list1," where list1 might hold N embedded lists
(more generally, Collections) instead of just three, I'd suggest a
recursive solution along the lines of:

	void tuples(List bigList, int which, String soFar) {
	    if (which < bigList.size()) {
	       for (Object item : bigList.get(which)) {
	           tuples(bigList, which + 1, soFar + item);
	       }
	    } else {
	        System.out.println(soFar);
	    }
	}
	...
	tuples(list1, 0, "");

     If that's not what you want, please explain "complete set"
more fully.

-- 
esosman@comcast-dot-net.invalid
Twelve hundred seventy-three days to go.