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Given a list of employees with properties Name and Department, how would you use GroupBy to create a dictionary where keys are departments and values are lists of employee names?

hard🚀 Application Q15 of Q15

C Sharp (C#) - LINQ Fundamentals

Given a list of employees with properties Name and Department, how would you use GroupBy to create a dictionary where keys are departments and values are lists of employee names?

Avar dict = employees.GroupBy(e => e.Name).ToDictionary(g => g.Key, g => g.Select(e => e.Department).ToList());

Bvar dict = employees.ToDictionary(e => e.Department, e => e.Name);

Cvar dict = employees.GroupBy(e => e.Department).ToList();

Dvar dict = employees.GroupBy(e => e.Department).ToDictionary(g => g.Key, g => g.Select(e => e.Name).ToList());

Step-by-Step Solution

Solution:

Step 1: Group employees by Department
Use GroupBy with key selector e => e.Department to group employees by their department.
Step 2: Convert groups to dictionary with employee names list
Use ToDictionary with key as group.Key (department) and value as list of employee names using g.Select(e => e.Name).ToList().
Final Answer:
var dict = employees.GroupBy(e => e.Department).ToDictionary(g => g.Key, g => g.Select(e => e.Name).ToList()); -> Option D
Quick Check:
GroupBy + ToDictionary with Select names = correct [OK]

Quick Trick: GroupBy then ToDictionary with Select for values list [OK]

Common Mistakes:

MISTAKES

Using ToDictionary directly without grouping
Grouping by Name instead of Department
Not converting grouped items to list of names

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