How to break from the loop when adding values to the list object which is distinct from already added values of the list?

Question

i have one list object which contains int like below:

var list = new List<int>();
var ids=getting only ids from database.for Eg:1,2,1,3,5,6,3.

Now what i want to do is after fetching ids from datatabase i want to add in to my list object and if any differnt ids is added(eg:ids:2) then i want to break from the loop.

For Ex: After adding 1 in my list now if i try to add 2 which doesnt exist in my list object then i want to break from my loop with status different element found outside the loop.

Add values in the list object till duplicate value is found means add only duplicate values in my list object and if distinct value is found which is not already in the list then break from loop.Break from the loop after adding 1 in list because 2 is different and it is not already in the list object.

This is my code:

bool status;
for (var i = 0; i < ids.Count; i++)
{
    list.Add(ids);
}
//here i want status with different element found or not

Note:I just want to add only duplicates values in my list object until new id is found.

I don't quite understand your criterion, but `break;` will exit a for loop — NikolaiDante, Jan 22 '16 at 07:26
i just want to add duplicate values in list object until different ids is found. — I Love Stackoverflow, Jan 22 '16 at 07:28
Downvoters probably would like to see shorter sentences, more punctuation and overall better English. Welcome to stack overflow. — Amadeusz Wieczorek, Jan 22 '16 at 07:35
@AmadeuszWieczorek: it's not only the english which makes it difficult to understand the requirement, but also OP's code that is a mixture of pseudo- and trivial code that seems not to be related to the requirement. @OP: What's the desired result of `status` at all? — Tim Schmelter, Jan 22 '16 at 09:25

Amadeusz Wieczorek · Answer 1 · 2016-01-22T08:22:54.740

2

You can use foreach to iterate over elements of ids
break works in foreach just the way it does in for
if we don't break, do whatever you want to do, for example, add the value to list
Contains checks if list already contains id.
- This makes it roughly an O(n^2) operation - because both foreach and Contains iterate over elements of list

Code:

foreach (var id in ids)
{
  if (list.Contains(id))
  {
    break;
  }
  list.Add(id);
}

edited Jan 22 '16 at 08:22

answered Jan 22 '16 at 07:34

Amadeusz Wieczorek

3,139
2
28
32

Please add some explanation to your answer! – ρss Jan 22 '16 at 08:12
i was expecting asnwer like what Tim Tim Schmelter has given on this question:http://stackoverflow.com/questions/18303897/test-if-all-values-in-a-list-are-unique – I Love Stackoverflow Jan 22 '16 at 09:11
1

@Learning if you expect this kind of answer, better communicate what you already did and what you want to do - judging by your question, I thought your problem is trivial and that you don't need extremely optimized code. – Amadeusz Wieczorek Jan 22 '16 at 17:55

score 2 · Answer 2 · answered Jan 22 '16 at 07:35

2

i just want to add duplicate values in list object until different ids is found.

var list = new List<int>{ 1, 2, 3, 4};
var idsFromDb = new List<int> {1, 2, 5, 3};

foreach (int id in idsFromDb)
{
    if (list.Contains(id))
    {
        break;
    }
    list.Add(id);
}

answered Jan 22 '16 at 07:35

Lukasz Pyrzyk

418
4
9

i was expecting asnwer like what Tim Schmelter has given on this question:http://stackoverflow.com/questions/18303897/test-if-all-values-in-a-list-are-unique – I Love Stackoverflow Jan 22 '16 at 09:11

Ian · Accepted Answer · 2016-01-22T09:18:08.667

1

You can use Contains

status = false;
for (var i = 0; i < ids.Count; i++)
{
    if (list.Count > 0 && !list.Contains(ids[i])){            
        list.Add(ids[i]); //add this, be it duplicate or not
        status = true; //different element found
        break; //break if this is not duplicate
    } else {
        //do something for duplicate
        list.Add(ids[i]); //add this, be it duplicate or not
    }
}

Contains can check if your item already exists in the List

edited Jan 22 '16 at 09:18

answered Jan 22 '16 at 07:32

Ian

30,182
19
69
107

i was expecting asnwer like what Tim Tim Schmelter has given on this question:http://stackoverflow.com/questions/18303897/test-if-all-values-in-a-list-are-unique – I Love Stackoverflow Jan 22 '16 at 09:09
with your ans when adding 1 it will go in first condition only and wont check for next distinct number – I Love Stackoverflow Jan 22 '16 at 09:15
@Learning are you implying that you want your first element to be treated differently? or when the list is empty the behavior will be adding the item? Because when your list is empty, then any item isn't a duplicate. – Ian Jan 22 '16 at 09:17
1

@Learning I added the condition for `list.Count > 0` – Ian Jan 22 '16 at 09:18
I wanted some advice from you.Can you please help me – I Love Stackoverflow Apr 12 '16 at 04:45
@Learning hi, long time not see. Whats that? – Ian Apr 12 '16 at 04:52
lets talk on chat.let me send you invite – I Love Stackoverflow Apr 12 '16 at 04:54

score 1 · Answer 4 · edited May 23 '17 at 10:29

1

Here's your desired HashSet<T> + LINQ approach:

var dupChecker = new HashSet<int> {ids[0]};  // add first element, now only duplicates are allowed
List<int> dupList = ids.TakeWhile(i => !dupChecker.Add(i)).ToList();

edited May 23 '17 at 10:29

Community

1
1

answered Jun 06 '16 at 10:42

Tim Schmelter

450,073
74
686
939

1

Thanks.Replied after 5 months but still i appreciate your answer – I Love Stackoverflow Jun 06 '16 at 11:34

How to break from the loop when adding values to the list object which is distinct from already added values of the list?

4 Answers4

Linked