Adding values to a C# array

Question

Probably a really simple one this - I'm starting out with C# and need to add values to an array, for example:

int[] terms;  for(int runs = 0; runs < 400; runs++) {     terms[] = runs; } 

For those who have used PHP, here's what I'm trying to do in C#:

$arr = array(); for ($i = 0; $i < 10; $i++) {     $arr[] = $i; } 

Answer 1

You can do this way -

int[] terms = new int[400]; for (int runs = 0; runs < 400; runs++) {     terms[runs] = value; } 

Alternatively, you can use Lists - the advantage with lists being, you don't need to know the array size when instantiating the list.

List<int> termsList = new List<int>(); for (int runs = 0; runs < 400; runs++) {     termsList.Add(value); }  // You can convert it back to an array if you would like to int[] terms = termsList.ToArray(); 

Edit: a) for loops on List<T> are a bit more than 2 times cheaper than foreach loops on List<T>, b) Looping on array is around 2 times cheaper than looping on List<T>, c) looping on array using for is 5 times cheaper than looping on List<T> using foreach (which most of us do).

Answer 2

Using Linq's method Concat makes this simple

int[] array = new int[] { 3, 4 };  array = array.Concat(new int[] { 2 }).ToArray(); 

result 3,4,2