Hello,

how can I define the range for the sum function which I want to sum up? For instance how do I sum up the first 3 elements of an array

int[] a = [1,2,3,4,5,6,7,8,9];

or the last 3?

On Thursday 10 September 2015 15:48, Namal wrote:

> Hello,
> 
> how can I define the range for the sum function which I want to sum up? For instance how do I sum up the first 3 elements of an array
> 
> int[] a = [1,2,3,4,5,6,7,8,9];
> 
> or the last 3?

First you slice the first/last 3, then you sum them.

first 3: a[0 .. 3].sum
last 3: a[$ - 3 .. $].sum

On Thursday, 10 September 2015 at 13:48:16 UTC, Namal wrote:
> Hello,
>
> how can I define the range for the sum function which I want to sum up? For instance how do I sum up the first 3 elements of an array
>
> int[] a = [1,2,3,4,5,6,7,8,9];
>
> or the last 3?

In this case, you can simply slice array using   a[0..3] or a[$-3..$].

If you have a range you can use take() and/or drop()

void main()
{
	
	int[] a = [1,2,3,4,5,6];
	
	writeln(a[0..3]);
	writeln(a[$-3..$]);
	writeln(a.take(3));
	writeln(a.drop(a.length-3));
	
}