On Fri, 03 Sep 2010 14:32:47 +0400, Bert van Leeuwen <[email protected]> wrote:
Pelle Wrote:
On 09/03/2010 11:42 AM, Bert van Leeuwen wrote:
> 2) Related to above, I want to do something like map, but not return
a new array, I want to modify elements in-place in the array. How do I
do that? (without explicitly iterating with foreach etc.)
I don't know if this is intended to be supported, but at least for now
this works:
int[] xs = [1,2,3,4,5,6,7];
copy(map!`a*a`(xs), xs);
writeln(xs);
[1, 4, 9, 16, 25, 36, 49]
Interesting. For large arrays, that seems to take almost double the time
of creating a new one with array() (as in Nick's reply). So copy()
obviously doesn't do it in place (not surprising given its name), and
presumably makes a temporary array first from which to copy to a.
I don't think you are right.
This is how copy is defined in std.algorithm[1]:
Range2 copy(Range1, Range2)(Range1 source, Range2 target)
if (isInputRange!Range1 && isOutputRange!(Range2, ElementType!Range1))
{
for (; !source.empty; source.popFront())
{
put(target, source.front);
}
return target;
}
[1]
http://dsource.org/projects/phobos/browser/trunk/phobos/std/algorithm.d#L4054
