On Tuesday, 12 September 2017 at 01:13:29 UTC, Hasen Judy wrote:
Is this is a common beginner issue? I remember using an earlier
version of D some long time ago and I don't remember seeing
this concept.
Now, a lot of library functions seem to expect ranges as inputs
and return ranges as output.
Even parsing a csv line returns a range. And the funny thing
is, once you loop over it, it's done. You've basically consumed
it.
For example, I was having some trouble with the api of the
std.csv module, so to help me debug, I printed the result of
the csv. ok, the result seems good. Now I try to use it, for
example:
auto name = row[1];
And to my surprise there's a runtime error, something about
range something something. I don't even remember what the error
was. The thing is, it wasn't clear what was going on.
The line was actually more like:
auto some_var =
some_function(row[1].some_other_library_method!template_variable);
So because I was calling several library methods on the same
line, I thought the problem might have something to do with the
range not exactly matching what the library was expecting. I
thought maybe row[1] also returned some range instead of a
string and that range had something wrong with it.
Well, it turned out that my earlier attempt to print the parsed
csv row resulted in the row being "consumed" and now the row is
an empty range(!).
Is there a straight forward way to convert a Range to a list
other than manually doing a foreach?
string[] items;
foreach(item; someRangeThing) {
items ~= item;
}
I feel like that is a bit of an overkill.
if `range.save` works use that, otherwise
`range.dup` will duplicate the range
or `range.array` (from std.array) will enumerate the range into
an array (which is pretty much the same as your solution above.
