how to remove repeating elements in an array using LINQ?remove an element if its repeating?

Question

int [] n=new int[10]{2,3,33,33,55,55,123,33,88,234};
output=2,3,123,88,234;

use LINQ i can do it using two for loops by continuously checking.but i need a more simple way using LINQ

its not removing duplicates.. removing duplicates by distinct will give = 2,3,123,33,55,88,234 my output should be = 2,3,123,,88,234;

adding the example of what you wanted exactly should have been done initially... — Mitch Wheat
– Mitch Wheat, Commented Jul 6, 2014 at 4:05
pleas be sure about the questions...its not just removing duplicates.. — Lijo
– Lijo, Commented Jul 6, 2014 at 4:06
i have added the output i wanted..its different from the answer given in removing duplicates — Lijo
– Lijo, Commented Jul 6, 2014 at 4:06
I have edited your title. Please see, "Should questions include “tags” in their titles?", where the consensus is "no, they should not". — John Saunders
– John Saunders, Commented Jul 6, 2014 at 5:40

Dmitrii Dovgopolyi · Accepted Answer · 2014-07-06 04:46:03Z

6

I combined your grouping idea and matiash's count. Not sure about its speed.

var result = n.GroupBy(s => s).Where(g => g.Count() == 1).Select(g => g.Key);

Update: i have measured the speed and it seems the time is linear, so you can use it on large collections

edited Jul 6, 2014 at 4:46

answered Jul 6, 2014 at 4:34

Dmitrii Dovgopolyi

6,2972 gold badges29 silver badges44 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

matiash Over a year ago

Congratulations, sir! This is way better :)

qbik Over a year ago

GroupBy should have O(n) complexity (see this question, it refers to SQL Group By operation, but the principle is the same). Filtering and selecting will also be O(n). One note: when testing the performance of answers (and Linq queries in general), be sure to call ToArray() or ToList() at the end. Most of Linq methods use yield internally, so the real computation can be deffered until you do an enumeration on the result. Calling ToArray() makes sure this enumeration happens and you measure the full running time.

Lijo Over a year ago

linq for getting the most repeated word in a string?

Dmitrii Dovgopolyi Over a year ago

@Lijo you should create a new question for this one. Comments are not an appropriate place.

Community · Accepted Answer · 2017-05-23 12:05:44Z

4

var result = n.Where(d => n.Count(d1 => d1 == d) <= 1);

This reads: only take those elements that are present at most 1 times in n.

It's quadratic though. Doesn't matter for short collections, but could possibly be improved.

EDIT Dmitry's solution is linear, and hence far better.

edited May 23, 2017 at 12:05

CommunityBot

11 silver badge

answered Jul 6, 2014 at 4:06

matiash

55.4k16 gold badges129 silver badges157 bronze badges

5 Comments

Mitch Wheat Over a year ago

make sure you heed the bit that says: "It's quadratic though"

Lijo Over a year ago

can you explain i didnt got what you commented

Lijo Over a year ago

its working and this what i needed..oh.. i think if we use this for large collections it will be slow that what you mean

matiash Over a year ago

@404 it means that the time needed will increase as the square of the number of items. In particular, for an input twice as large, it will take four times as long. So for big collections it could be unwieldly.

Vaughan Hilts Over a year ago

I made an attempt at a slightly faster (alebit not compeltely pure LINQ) solution.

Collectives™ on Stack Overflow

how to remove repeating elements in an array using LINQ?remove an element if its repeating?

2 Answers 2

4 Comments

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related