c# collection

Question

Hi and hello everybody...

I am beginner to the c# collections , i can't understand the exact need of iEnumerable's advantages, if anybody gives the difference between the following two type of codes, would be great thing for me to understand what i need, thanks in advance guys...

Type1:
int[] integers = { 1, 9, 5, 3, 7, 2, 11, 23, 50, 41, 6, 8 };
IEnmerable<int> takeWhileNumber = integers.TakeWhile(num =>
num.CompareTo(50) != 0);

Type2:
int[] takeWhileNumber ;
int[] integers = { 1, 9, 5, 3, 7, 2, 11, 23, 50, 41, 6, 8 };
takeWhileNumber = integers.TakeWhile(num =>
num.CompareTo(50) != 0);

Manas Mohapatra · Answer

Hi When we write any LINQ it always returns IEnumerable type. So when use integer array with LINQ(type2) then you need to convert it to array otherwise it will give you compilation error. You need use takeWhileNumber = integers.TakeWhile(num => num.CompareTo(50) != 0). ToArray (); But in case of IEnumerable it doesn't need any conversion. Secondly if you want to make your result set readonly and want to display data only then IEnumerable faster than other List Array. Thirdly IEnumerable supports only foreach to looping over resultset. But incase of array you use foreach for loop. Fourthly you can the elements through index in array but it is not possible in case of IEnumerable. So use them wisely as per your requirement.