Using C# and Linq to create an array containing unique items from two input arrays

Question

I have two string arrays containing file names. From those two arrays, I need to produce a third string array that contains only the file names that are unique (i.e., found in one array, but not in both arrays).

Lee · Accepted Answer · 2014-03-15 15:28:47Z

6

var elements = array1.Union(array2).Except(array1.Intersect(array2));

answered Mar 15, 2014 at 15:28

Lee

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4 Comments

Strax Tillbaka Over a year ago

The coders on StackOverflow also never cease to amaze!

Adam Houldsworth Over a year ago

@grant probably because of the Except call. It isn't needed.

jdphenix Over a year ago

Read the spec, @StraxTillbaka basically wants XOR on an array, `A⊕B == (A AND B) NOT (A OR B), Lee's code does exactly that

Adam Houldsworth Over a year ago

@jdpenix true, I paid too nuch attention to the unique description, not the ie bit :-)

jdphenix · Accepted Answer · 2014-03-15 16:07:23Z

1

Consider using HashSet<T>. It has an implementation of exactly what you're looking for.

var setA = new HashSet<string>(arrayA);  
setA.SymmetricExceptWith(arrayB); // setA is mutated

Obviously, you'll need to measure if the cost of initializing a HashSet is worth it.

edited Mar 15, 2014 at 16:07

answered Mar 15, 2014 at 15:49

jdphenix

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