Select a dictionary with certain properties of a class

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I have a Student class as follows :

public class Student
{
    public string Name { get; set; }
    public int? Age { get; set; }
    public bool? IsMale { get; set; }
}

and have list of courses where Students are assigned as a Dictionary, where all courses are stored as:

Dictionary<string, List<Student>>

where Key (string) is the code of the course and the Value (List< student >) are the students enrolled to that spesific course with all properties having a value.

Now I want to simplify the data set with only the Name of the students. So I will still have a Dictionary<string, List<Student>> where only the Name property is set for each and every Student object.

How can I write such a LINQ query to fetch the data as I need?

linq c#
1 Answers

Since the dictionary implements IEnumerable<KeyValuePair<string, List<Student>>>, you can write

var newDict = oldDict
    .ToDictionary(
        kvp => kvp.Key,
        kvp => kvp.Value.Select(s => new Student { Name = s.Name }).ToList()
    );

Note that we have a nested LINQ query based on the list of students. It selects all the students of the list and creates new students with only the name set into a new list.

So, for each KeyValuePair, we keep the Key (the course code), but create a new Value as simplified list of students.

Instead, you could also create a Dictionary<string, List<string>> with

var newDict = oldDict
    .ToDictionary(
        kvp => kvp.Key,
        kvp => kvp.Value.Select(s => s.Name).ToList()
    );
user_8809900
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