Array in another bigger array including duplicates using Linq

Question

Example: Array1.Intersect(Array2) checks for only distinct elements.

Is there an elegant way using linq to get the result which contains even duplicates? The result should be case-insensitive. Thanks.

input: string[] Arr1= new string[] { "a","a", "b", "y" }; string[] Arr2= new string[] {"s", "a", "z", "b", "c", "a"}; Output {"a", "a", "b"} but not {"a", "b"} — user1191177
– user1191177, Commented Apr 29, 2013 at 10:47

Tim Schmelter · Accepted Answer · 2013-04-29 10:50:01Z

4

Not as efficient but clear:

var inboth = Array1.Where(Array2.Contains);

Edit according to your case-insensitive comment:

inboth = Array1.Where(s => Array2.Contains(s, StringComparer.OrdinalIgnoreCase));

edited Apr 29, 2013 at 10:50

answered Apr 29, 2013 at 10:39

Tim Schmelter

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5 Comments

Jodrell Over a year ago

converting Array2 to a HashSet might make things more efficient if there are enough elements in Array1, either way this works.

user1191177 Over a year ago

Thanks Tim. However I forgot to mention that the result should also contain case-insensitive elements.

Tim Schmelter Over a year ago

@user1191177: You haven't even told that the arrays are String[]. However, give me a moment.

Jodrell Over a year ago

you could consider using the current culture over ordinal, I know ordinal would be faster but in some cultres things change more when you shift case (I think.) The HashSet option is still available, as shown in my improved answer.

Tim Schmelter Over a year ago

Most people want to compare culture-agnostic and even if he wants to take the current culture into account, as far as i know Ordinal passes the turkey test since it behaves like ToUpper(instead of the dangerous ToLower).

Jodrell · Accepted Answer · 2013-04-29 10:57:42Z

0

after your comment,

var secondSet = new HashSet<string>(
    array2,
    StringComparer.CurrentCultureIgnoreCase);

var intersectSequence = array2.Where(secondSet.Contains);

edited Apr 29, 2013 at 10:57

answered Apr 29, 2013 at 10:50

Jodrell

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