Scala code crashing with java.util.NoSuchElementException: next on empty iterator

Question

My code is crashing with java.util.NoSuchElementException: next on empty iterator exception.

def myfunction(arr : Array[(Int,(String,Int))]) = {
val values = (arr.sortBy(x => (-x._2._2, x._2._1.head)).toList)
...........................

The code is crashing in the first line where I am trying to sort an array.

var arr = Array((1,("kk",1)),(1,("hh",1)),(1,("jj",3)),(1,("pp",3)))

I am trying to sort the array on the basis of 2nd element of the inner tuple. If there is equality the sort should take place on first element of inner tuple.

output - ((1,("pp",3)),(1,("jj",3)),(1,("hh",1)),(1,("kk",1)))

This is crashing under some scenarios (normally it works fine) which I guess is due to empty array.

How can I get rid of this crash or any other elegant way of achieving the same result.

Answer 1

It happens because one of your array items (Int,(String,Int)) contains empty string.

"".head

leads to

java.util.NoSuchElementException: next on empty iterator

use x._2._1.headOption

Answer 2

val values = (arr.sortBy(x => (-x._2._2, x._2._1)).toList)

Removing head from the statement works.This crashes because of the empty string in arr

var arr = Array((1,("kk",1)),(1,("hh",1)),(1,("jj",3)),(1,("pp",3)),(1,("",1)))