On Sunday, 19 January 2014 at 06:57:37 UTC, CJS wrote:
Ah, I'd been wondering if there was something like this. But
why does it need unitlist's address? (Assume & has the same
meaning as in C and C++.)
Look at the docs for Appender. It can either provide its own
storage, or use an existing one. In the latter case you feed it a
pointer to your array and it uses that.
This one seems like it should be unitlist.filter!(x =>
x.any!(y => s==y)).array();
Oh. Duh. But what is the .array() at the end doing? Allocating
a new array for the results of the filter, since it's basically
just a lazily computed range rather than actual storage for the
results?
Yes. But in this case you'd have to allocate anyways, to fill the
units[s] array.
I'm just trying to match what the python code was doing. In
that case the line
Ah, I see.
peers = dict((s, set(sum(units[s],[]))-set([s]))
for s in squares)
was using sum to concatenate a bunch of lists together and then
remove the element. But I miscounted the parentheses and didn't
notice the '-' was after the concatenated lists were tured into
a set. The following code appears to do what I want, but the
string temporary and appender are a bit ugly. Any suggestions
on getting rid of them?
foreach(s; squares){
peers[s] = units[s].join().sort().uniq().filter!(a =>
a!=s).array();
}
That's std.array.join() there. However, I notice that the output
(the order of elements) differs from the one on that page you
linked earlier.
