Append a value in dictionary .net

Question

I want to append a string value in my dictionary in .net however I couldn't find an information about it for .net. Here is my dictionary which is set already with key-value pairs:

Dictionary<int, string> mydict = new Dictionary<int, string>();

I want to append new strings into existing ones in values.

For example: If we have <1,A> pair I want to append it to <1,AB>. Does anybody know a way to do this?

Perhaps you actually need a `Dictionary>`? – Charlieface Mar 24 '21 at 08:33 — Charlieface, Mar 24 '21 at 08:33

score 1 · Accepted Answer · edited Mar 24 '21 at 08:28

1

Well I am not sure what you trying to do, but let me guess: if you have key which exists, you want to append to the corresponding value, if not, insert new key-value pair? If so, see code bloew:

var key = 1;
var val = "new value to append";
if (myDict.CotainsKey(key))
{
    myDict[key] += val;
}
else
{
    myDict.Add(key, val);
}

edited Mar 24 '21 at 08:28

Joel

5,732
4
37
65

answered Mar 24 '21 at 08:25

Michał Turczyn

32,028
14
47
69

I see, I was looking for a LINQ way but thank you – B B Mar 24 '21 at 08:32
@BB LINQ is for querying, not for manipulating data – SomeBody Mar 24 '21 at 08:37
Please use `TryGetValue` https://stackoverflow.com/questions/9382681 you will save a look-up in the dictionary if the key is already there. – Orace Mar 24 '21 at 08:41
1

Here is your one-liner: `myDict[key] = (myDict.TryGetValue(key, out var s) ? s : "") + val;` – Charlieface Mar 24 '21 at 09:18

Append a value in dictionary .net

1 Answers1