How do i use a List which is inside a Dictionary-CodePudding

let's say I want to make a program that takes as input: {personName} {food1} {food2} ... {foodN}. Then they should be stored in a Dictionary - The Key should be the {personName}, and the Value should be a list that stores all the food[n], that is in the input. Then i want to print them like this {personName} -> {food1}, {food2}, {food3} ... {foodN}.

using System;
using System.Collections.Generic;
using System.Linq;

namespace stack1
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();  // George, Pizza, Burger
            Dictionary<string, List<string>> peopleFood = new Dictionary<string, List<string>>();
            while (input != "stop")
            {
                List<string> inputs = input.Split(" ").ToList(); // George, Pizza, Burger
                peopleFood.Add(inputs[0], inputs[1], inputs[2]); // George, Pizza, Burger
                input = Console.ReadLine(); //stop
            }
            Console.WriteLine(); // George -> Pizza, Burger
        }
    }
}

The .Add function is not working with 3 elements, and I don't know what else to use. The same goes for the printing process - I don't know how to print the output i want .

CodePudding user response：

The .Add function is not working with 3 elements

Because the .Add method is expecting two arguments. A string and a List<string>. Provide those arguments:

peopleFood.Add(inputs[0], new List<string> { inputs[1], inputs[2] });

Or perhaps:

peopleFood.Add(inputs[0], inputs.Skip(1).ToList());

I don't know how to print the output i want

I don't know how you want to format that output, but in general you can (1) loop over the dictionary and, for each element, (2) loop over the list. For example:

foreach (var item in myDictionary)
    foreach (var val in item.Value)
        Console.WriteLine(val);

CodePudding user response：

The Add function expects a Key=string as first argument and a Value=list of strings as second argument. It will not magically interpret any other arguments you give it.

input.Split(" ") will generate a string[]. You can use that directly with (ranged) indexing.

inputs[0] would be the first element and inputs[1..].ToList() will make you a new list of the rest. There you have your arguments.

Note, you will have to check yourself if the original input actually consist of enough strings.

CodePudding user response：

Both the previous responders, David and JHBonarius, gave good answers and warnings about why your attempt to add values to the dictionary wasn't working. So I won't repeat that. There currently aren't any answers about how to get the output in the format you want (name -> food list). You could do something like this after your while loop to achieve that:

Console.Write(String.Join("\n"), peopleFood.Select(kvp => kvp.Key   " -> "   String.Join(", ", kvp.Value))));
Console.ReadLine();