Create Dictionary(of Dictionary) using Grouping in Linq

Question

I know I could do this with loops (as a matter of fact, I currently am, but I am trying to learn / imporve my Linq skills and i also hope it will provide a more efficent sol

Answer 1

I only C#, not VB. Apologies in advance.

Let's start by making a single list of anonymous objects with properties teacher, sex, name:

var singleList = lstTeachers
  .Zip(lstStudentsSex, (teacher, sex) => new {teacher, sex})
  .Zip(lstStudentName, (x,name) => new {x.teacher, x.sex, name})

Now we can turn this into a Dictionary of Dictionaries:

singleList
  .GroupBy(x => x.teacher)
  .ToDictionary(
       g => g.Key, 
       g => g.ToDictionary(x => x.sex, x => x.name))

See @nawfal's for a corrected version of my code.