On 8/6/22 18:22, pascal111 wrote:
> Why we use "chain" while we have "~":
>
> '''D
> int[] x=[1,2,3];
> int[] y=[4,5,6];
>
> auto z=chain(x,y);
> auto j=x~y;
> '''
To add to what has already mentioned,
- chain can be used on ranges that are of different element types
- as usual, some of the ranges may be generators
- although obscure, one may sort in-place over multiple ranges (requires
RandomAccessRange.)
This program shows the first two points:
import std; // Apologies for terseness
void main() {
auto ints = [ 10, 3, 7 ];
auto squares = iota(10).map!squared.take(5);
auto doubles = [ 1.5, -2.5 ];
auto c = chain(ints, squares, doubles);
// Different types but CommonType is 'double' here:
static assert(is(ElementType!(typeof(c)) == double));
// Prints [10, 3, 7, 0, 1, 4, 9, 16, 1.5, -2.5]
writeln(c);
}
auto squared(T)(T value) {
return value * value;
}
And this one shows how one can sort in-place multiple arrays:
import std; // Ditto
void main() {
auto a = [ 10, 3, 7 ];
auto b = [ 15, -25 ];
auto c = chain(a, b);
sort(c);
writeln(a); // Prints [-25, 3, 7]
writeln(b); // Prints [10, 15]
}
Ali
