Question

private List<String> subList;
private List<List<String>> records = new ArrayList<List<String>>();

for(....){

    subList = new ArrayList<String>();
    ...populate..
    records.add(subList);
}

For example, subList has three Strings – a, b, and c.
I want to sort the records by the value of b in subList.

records at 0 has a list of "10", "20", "30"
records at 1 has a list of "10", "05", "30"
records at 2 has a list of "10", "35", "30"

After the sort, the order of records should be –

records at 0 = records at 1 above
records at 1 = records at 0 above
records at 2 = records at 2 above

What could be a good algorithm for that?

Answer 1

Something like:

Collections.sort(records, new Comparator<List<String>>()
{
  public int compare(List<String> o1, List<String> o2)
  {
    //Simple string comparison here, add more sophisticated logic if needed.
    return o1.get(1).compareTo(o2.get(1));
  }
})

Though I find hard-coding the positions a little dubious in practice, your opinion may differ.