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Combining two collections, but only for objects with the corresponding identifier

First of all, apologize if this is a blatant duplicate, I was looking for all phrases that could give a result, but I struggled to find an answer / construct search terms coherently.

I have collection 1 and collection 2 of object A.

// Object A Structure
Date
Type
Value

Collection 1 covers dates 1 to 2 for type 2, and collection 2 covers dates 3 to 4 for type 1:

// Collection 1
[0] = 1st, TypeA, 3
[1] = 2nd, TypeA, 3
[2] = 1st, TypeB, 57
[3] = 2nd, TypeB, 57

// Collection 2
[0] = 3rd, TypeB, 57
[1] = 4th, TypeB, 58

My initial requirement was to combine the two collections. No problem:

var result = collection1.Union(collection2);

However, now I would like to combine both collections, but excluding objects from Collection 1, where the Type does not exist in Collection 2:

// Result Collection
[0] = 1st, TypeB, 57
[1] = 2nd, TypeB, 57
[2] = 3rd, TypeB, 57
[3] = 4th, TypeB, 58

I'm sure there is a simple (hopefully linq) single line solution, but I just can't make my brain understand what it is.

The best (two lines) I've got so far:

// Get distinct Types from Collection 2
var typesToInclude = collection2.GroupBy(c => c.Type).Select(group => group.First().Type);

var result = collection2.Union(collection1.Where(c => typesToInclude.Contains(c.Type)));

: (

+3
1

var result = collection1
  .Where(x => collection2.Any(c => c.Type == x.Type))
  .Union(collection2);

collection1 , Type collection2,

+7

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