CODEWITHSUNDEEP
c#.netlinqlinq-to-objects
Nick
Nick

Reputation: 7525

Adding or updating dictionary elements using Linq

I need to check if a key exists and accordingly to an add or an update in the dictionary.

        if (dict.ContainsKey("Key1"))
            dict["Key1"] = "Value1";
        else
            dict.Add("Key1", "Value1");

Can I simplify this using Linq or otherwise?

Upvotes: 0

Views: 5631

Answers (3)

dexter
dexter

Reputation: 7203

You can also use something like this:

 Dictionary<string, string> dict = new Dictionary<string, string>();
        dict.Add("1", "1");
        dict.Add("2", "2");

        var x = dict.Where(q => q.Key == "1");
        if (x.Any())
            dict[x.FirstOrDefault().Key] = "new";

Upvotes: 0

diceguyd30
diceguyd30

Reputation: 2752

Not really...linq is a query language and is not intended to mutate data structures. You can sort of get around this, but you shouldn't consider your code wrong just because it isn't linq. The only line you could add to the code you posted to 'linq-ify' it would be to change dict.ContainsKey("Key1") to dict.Any(x => x.Key == "Key1"), but don't do this as it will no doubt be slower. I actually think Darin's answer is quite elegant and recommend you use it!

Upvotes: 0

Darin Dimitrov
Darin Dimitrov

Reputation: 1038850

You can simplify your 4 lines of code to this:

dict["Key1"] = "Value1";

If Key1 doesn't exist in the dictionary it will be added and if it exists the value will be updated. That's what the indexer does. As far as LINQ is concerned I don't see any relation to the question.

Upvotes: 8

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