CODEWITHSUNDEEP
javalistarraylist
Priya
Priya

Reputation: 339

forming new small lists from a combination set of two lists

I have two patterns of lists inside a big list. 

[[5.35, 5.09, 4.95, 4.81, 4.75, 5.19], [3601.0, 3602.0, 3603.0, 3600.0, 3610.0, 3600.0],[..,..,..,],[..,..,..],...]

To put in simple words, it is a combination of

[ [pricesList1], [DurationList1], [PricesList2], [DurationList2],... ]

I now want to create a new list with the price and corresponding duration from both lists as a pair from each set. For Example :

[[[5.35,3601.0],[5.09,3602.0],[4.95,3603],[4.81,3600],[4.75,3610],....],[[p1,d1],[p2,d2],[p3,d3],..],[[],[],[],..],....]

I have tried using List<List<Object>> and List<List<String>>. But no use. How can I do this?

I programed as following, which is wrong :

List<List<Object>> DurationList = new ArrayList<List<Object>>();
List<List<Object>> FinalList = new ArrayList<List<Object>>();
List<List<String>> SlotList = null;
for(int pair=0; pair<(FinalList.size()-1) ; pair=pair+2)
                {
                    for(int innerloop=0; innerloop<(FinalList.get(pair).size());innerloop++)
                            {
                            SlotList = new ArrayList<List<String>>();
                            SlotList.addAll((Collection<? extends List<String>>) (FinalList.get(pair).get(innerloop)));
                            }
                }
for(int pair=1; pair<(FinalList.size()) ; pair=pair+2)
                {
                    for(int innerloop=0; innerloop<(FinalList.get(pair).size());innerloop++)
                            {
                            SlotList.addAll((Collection<? extends List<Object>>) FinalList.get(pair).get(innerloop));
                            }
                }

Upvotes: 0

Views: 54

Answers (1)

Aaron
Aaron

Reputation: 24812

Assuming the input list always has an even number of sublists and pairs of sublists have the same size, you can use a for loop iterating over the outer lists's element two by two :

List<List<String>> result = new ArrayList<>();
for (int i=0; i<outerList.size(); i+=2) {
    List<String> priceList = outerList.get(i);
    List<String> durationsList = outerList.get(i+1);
    for (int j=0; j<priceList.size(); j++) {
        List<String> newEntry = new ArrayList<>();
        newEntry.add(priceList.get(j));
        newEntry.add(durationsList.get(j));
        result.add(newEntry);
    }
}

As commented I suggest defining your own class to store the price and duration rather than using that List<String> newEntry.

Upvotes: 1

Related Questions