Question

Referring to this question: How to subtract dates from each other

In Groovy, I’ve got a script that spits out the 5 largest values from a text file collection. How can I know what the indices of those values are?

Answer 1

If you have a list of things ie:

def list = [ 'c', 'a', 'b' ]

One way of knowing the original index would be to use transpose() to join this list to a counter, then sort the new list, then you will have a sorted list with the original index as the secondary element

ie:

[list,0..<list.size()].transpose().sort { it[0] }.each { item, index ->
  println "$item (was at position $index)"
}

To break that down;

[list,0..<list.size()]

gives us (effectively) a new list [ [ 'c', 'a', 'b' ], [ 0, 1, 2 ] ]

calling transpose() on this gives us: [ [ 'c', 0 ], [ 'a', 1 ], [ 'b', 2 ] ]

We then sort the list based on the first item in each element (the letters from our original list) with sort { it[0] }

And then iterate through each, printing out our now sorted item, and its original index location