even indices of an array

[graphicsxp]

Hi,

Is there a way using Linq of getting all the elements of an array for
which the index is uneven.

For instance in an array containing {3, 55, 21, 34}, I'd like to get 3
and 21.

Thanks

 

[Michael C]

Hi,

Is there a way using Linq of getting all the elements of an array for
which the index is uneven.

For instance in an array containing {3, 55, 21, 34}, I'd like to get 3
and 21.

I think this will work, I have have VS here at the moment to test.
MyArray.Where((i, j) => (j & 1) == 0);

 

[graphicsxp]

I think this will work, I have have VS here at the moment to test.
MyArray.Where((i, j) => (j & 1) == 0);

Could you explain ? Where are i and j coming from ? This surely can't
be complete code.

 

[miher]

Hi,
If You have an array You can simply go over it with a for loop, selecting
every other element.

If You insist on LINQ:
int c = 1;
var result = YourCollection.Where(i => c++ % 2 == 1);
(I feel this is a bit "hacky", but You can try.)

Hope You find this useful.
-Zsolt

 

[graphicsxp]

Hi,
If You have an array You can simply go over it with a for loop, selecting
every other element.

If You insist on LINQ:
int c = 1;
var result = YourCollection.Where(i => c++ % 2 == 1);
(I feel this is a bit "hacky", but You can try.)

Hope You find this useful.
-Zsolt

Yep, it's working. Why do you think it's 'hacky' ? I know how to do it
with a for loop but since i'm learning LINQ, I thought it looks neater
than a for loop.

Thanks !

 

[Stefan Hoffmann]

hi,

If You insist on LINQ:
int c = 1;
var result = YourCollection.Where(i => c++ % 2 == 1);
(I feel this is a bit "hacky", but You can try.)

Maybe

var result = YourCollection.Where((p, i) => i % 2 == 0);


mfG
--> stefan <--

 

[Göran Andersson]

Could you explain ? Where are i and j coming from ? This surely can't
be complete code.

The Where method has an overload that takes a Fun<T, int, bool> delegate.

The i parameter is the item to evaluate and the j parameter is the index
of the item.

(j & 1) gives you the least significant bit of the index. If that is
zero, you have an even number (which is what you want as the index is
zero based).

 

[miher]

Hi,
Thats really cool, i wasn't aware of this overload.
Thanks for the info.

-Zsolt