- I have a dataset. Columns represents different variables.
- A variable may start with NaN or any double type number.
- If it starts with double number it continues with double type numbers.
- If it starts with NaN, we do not know when it ends.
- Return the row index where last NaN is observed in overall dataset. (Think column-wise)
[ 1 NaN 5 NaN 2
2 NaN 4 4 8
6 NaN 8 2 4
0 0 0 0]
should return 3 because last NaN is observed in third row.
Test suite may be changed!