[Solved] Given a list of user IDs and names:var users = new List<(int id, string name)> { (1, "Alice"), (2, "Bob"), (3, "Charlie") };Which code correctly creates a Dictionary<int, string> mapping IDs to names... | C Sharp (C#)

C Sharp (C#) - Collections

Given a list of user IDs and names:

var users = new List<(int id, string name)> { (1, "Alice"), (2, "Bob"), (3, "Charlie") };

Which code correctly creates a Dictionary<int, string> mapping IDs to names using a dictionary comprehension style?

Avar dict = users.ToDictionary(u => u.id, u => u.name);

Bvar dict = new Dictionary<int, string>(); foreach(var u in users) dict.Add(u.name, u.id);

Cvar dict = users.Select(u => new { u.id, u.name }).ToList();

Dvar dict = new Dictionary<string, int>(); foreach(var u in users) dict[u.id] = u.name;

Step-by-Step Solution

Solution:

Step 1: Understand ToDictionary usage
ToDictionary converts a list to a dictionary by specifying key and value selectors.
Step 2: Check each option
var dict = users.ToDictionary(u => u.id, u => u.name); correctly maps id to name. var dict = new Dictionary<int, string>(); foreach(var u in users) dict.Add(u.name, u.id); swaps key and value and uses wrong types. var dict = users.Select(u => new { u.id, u.name }).ToList(); creates a list, not dictionary. var dict = new Dictionary<string, int>(); foreach(var u in users) dict[u.id] = u.name; has wrong dictionary types and indexer usage.
Final Answer:
var dict = users.ToDictionary(u => u.id, u => u.name); -> Option A
Quick Check:
ToDictionary creates dictionary from list [OK]

Quick Trick: Use ToDictionary with key and value selectors [OK]

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