LINQ - selecting second item in IEnumerable

Question

I have

string[] pkgratio= "1:2:6".Split(':');

var items = pkgratio.OrderByDescending(x => x);

I want to select the middle value and have come up with this. Is this a correct way to select the second value in an IEnumberable?

pkgratio.Skip(1).Take(1).First();

related to my first ever question: http://stackoverflow.com/questions/1735146/ways-to-get-the-middle-of-a-list-in-haskell — Matt Ellen, Sep 13 '10 at 14:03
Using `First()` implies you are confident that an item will actually be at the position you are attempting to access. If there is any doubt, you may wish to use `FirstOrDefault()`. — Anthony Pegram, Sep 13 '10 at 14:06

Ahmad Mageed · Accepted Answer · 2014-03-07T16:21:40.133

While what you have works, the most straightforward way would be to use the array's index and reference the second item (at index 1 since the index starts at zero for the first element): pkgratio[1]

Console.WriteLine(pkgratio[1]);

A more complete example:

string[] pkgratio = "1:2:6".Split(':');

for (int i = 0; i < pkgratio.Length; i++)
    Console.WriteLine(pkgratio[i]);

With an IEnumerable<T> what you have works, or you could directly get the element using the ElementAt method:

// same idea, zero index applies here too
var elem = result.ElementAt(1);

Here is your sample as an IEnumerable<string>. Note that the AsEnumerable() call is to emphasize the sample works against an IEnumerable<string>. You can actually use ElementAt against the string[] array result from Split, but it's more efficient to use the indexer shown earlier.

var pkgratio = "1:2:6".Split(':').AsEnumerable();
Console.WriteLine(pkgratio.ElementAt(1));

Worked with Linq for years now, and have never used ElementAt(). Busy writing some tests and needed it. Great simple answer — Peter Munnings, Jul 09 '13 at 09:04
Same here +1 for the ElementAt, now using ElementAtOrDefault too — jolySoft, Jun 15 '15 at 15:04

score 52 · Answer 2 · answered Sep 13 '10 at 14:04

52

I don't think you need to .Take(1).

pkgratio.Skip(1).First()

answered Sep 13 '10 at 14:04

Cheng Chen

42,509
16
113
174

BeRecursive · Answer 3 · 2013-02-22T16:01:54.030

23

pkgratio.ElementAt(1); for your scenario.

However, your method is only applicable if you were using some data that implemented IQueryable or you needed to take a range of items starting at a specific index eg:

pkgratio.Skip(5).Take(10);

edited Feb 22 '13 at 16:01

answered Sep 13 '10 at 14:04

BeRecursive

6,286
1
24
41

score 19 · Answer 4 · answered Sep 13 '10 at 14:05

19

Well, the Take(1) isn't strictly necessary if you're going to just First() it, so I might go with

pkgratio.Skip(1).First();

However, that First() will throw an exception if there no value, so you might want to try FirstOrDefault() and then check for null.

answered Sep 13 '10 at 14:05

Restore the Data Dumps

38,967
12
96
122

LINQ - selecting second item in IEnumerable

4 Answers4

Linked

Related