CODEWITHSUNDEEP
c#linq
Ole Albers
Ole Albers

Reputation: 9295

LinQ ofType in Value

I have the following Dictionary:

public Dictionary<string,object> Items;

Now I need to get all Items where the Value of the Dictionary-item is from a specific type. (e.g. "int")

var intValues = Items.OfType<KeyValuePair<string,int>> simply does not work.

Code without LinQ would be something like:

var intValues=new Dictionary<string,int>()
foreach (var oldVal in Items) {
  if (oldVal.Value is int) {
    intValues.add(oldVal.Key, oldVal.Value);
  }
}

(Update) my example should show the basic idea. But if possible I would avoid to create a new Dictionary as a result.

Upvotes: 3

Views: 413

Answers (4)

DavidG
DavidG

Reputation: 118977

You can use the is operator on the Value property:

var intValues = Items.Where(x => x.Value is int);

If you want an actual Dictionary<string,int> at the end just add:

.ToDictionary(v=> v.Key, v=> (int)v.Value)

Upvotes: 4

Nikhil Agrawal
Nikhil Agrawal

Reputation: 48568

You can do

var result = Items.Where(x => x.Value is int)
                  .ToDictionary(x => x.Key, x => x.Value);

Upvotes: 2

Alessandro D&#39;Andria
Alessandro D&#39;Andria

Reputation: 8868

Try with this:

var intValue = Items
    .Where(x => x.Value is int) // filter per Value is int
    .ToDictionary(x => x.Key, x => (int)x.Value); // create a new dictionary converting Value to int

Upvotes: 4

poke
poke

Reputation: 387707

The direct translation of your foreach would be the following in LINQ:

var intValues = Items.Where(item => item.Value is int)
                     .ToDictionary(item => item.Key, item => (int)item.Value);

So basically, you filter first for where the item.Value is an int, and then you create a dictionary from it using ToDictionary where you cast those values to int to make sure that the resulting dictionary is a Dictionary<string, int>. Since we filtered non-integers already, this type cast will always succeed.

Upvotes: 7

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