C# How to "array.add" to an array of a dictionary?

Question

Imagine that you have a dictionary like that:

Dictionary<int, int[]> dict = new Dictionary<int, int[]>();

So what I want to do is to ".add" to the value like a normal array.

I know I can add a Key and a Value like that:

dict.Add(0, new int[]{1, 2, 3, 4});

So I have this: Key=0, Value=[1, 2, 3, 4].

But what happen if I want to add a "5" at the value of the "Key=0" in order to make it appears like Key=0, Value=[1, 2, 3, 4, *5*]?

What you have to do is to extract the array and create a new one with the 5 at the end of it since Arrays have fixed size — fasaas
– fasaas, Commented Oct 13, 2018 at 17:16

adjan · Accepted Answer · 2018-10-13 17:21:00Z

2

To modify an an array inside a dictionary you could use LINQ's Append():

dict[0] = dict[0].Append(5).ToArray();

But you should not use arrays if you want to modify them. Use List<T> instead:

var dict = new Dictionary<int, List<int>>();

dict.Add(0, new List<int> {1,2,3,4});

Then you can call Append() on the list inside the dictionary:

dict[0].Append(5);

answered Oct 13, 2018 at 17:18

adjan

13.7k2 gold badges35 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Try dict[0].Add(5) given a List<int> inside a Dictionary 🙂