## digitalmars.D.learn - Sum and other algorithm functions

• Namal (6/6) Sep 10 2015 Hello,
• anonymous (4/13) Sep 10 2015 First you slice the first/last 3, then you sum them.
• Andrea Fontana (15/21) Sep 10 2015 In this case, you can simply slice array using a[0..3] or
"Namal" <sotis22 mail.ru> writes:
```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?
```
Sep 10 2015
anonymous <anonymous example.com> writes:
```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
```
Sep 10 2015
"Andrea Fontana" <nospam example.com> writes:
```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));

}
```
Sep 10 2015