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Given a list of products with properties Name and Category, how would you use GroupBy in C# to create a dictionary where keys are categories and values are lists of product names?

hard🚀 Application Q8 of Q15

C Sharp (C#) - LINQ Fundamentals

Given a list of products with properties Name and Category, how would you use GroupBy in C# to create a dictionary where keys are categories and values are lists of product names?

Avar dict = products.GroupBy(p => p.Category).ToDictionary(g => g.Key, g => g.Select(p => p.Name).ToList());

Bvar dict = products.ToDictionary(p => p.Category, p => p.Name);

Cvar dict = products.GroupBy(p => p.Name).ToDictionary(g => g.Key, g => g.Select(p => p.Category).ToList());

Dvar dict = products.GroupBy(p => p.Category).ToList();

Step-by-Step Solution

Solution:

Step 1: Group products by Category
Use GroupBy(p => p.Category) to group products by their category.
Step 2: Convert groups to dictionary
Use ToDictionary with key as group.Key (category) and value as list of product names in that group.
Step 3: Select product names
Use g.Select(p => p.Name).ToList() to get list of product names per category.
Final Answer:
var dict = products.GroupBy(p => p.Category).ToDictionary(g => g.Key, g => g.Select(p => p.Name).ToList()); -> Option A
Quick Check:
GroupBy then ToDictionary with key and projected values [OK]

Quick Trick: Group then project values before ToDictionary [OK]

Common Mistakes:

MISTAKES

Using ToDictionary directly without grouping
Grouping by wrong property
Not projecting group elements to desired value

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