http://d.puremagic.com/issues/show_bug.cgi?id=4468
Summary: std.string.join() for lazy iterable of strings
Product: D
Version: D2
Platform: All
OS/Version: All
Status: NEW
Severity: enhancement
Priority: P2
Component: Phobos
AssignedTo: nob...@puremagic.com
ReportedBy: bearophile_h...@eml.cc
--- Comment #0 from bearophile_h...@eml.cc 2010-07-15 17:24:25 PDT ---
This Python code generates a lazy sequence of the first 20 integers (starting
from 0), then maps them lazily to strings, and then joins them in a single
string:
from itertools import imap
r = imap(str, xrange(20))
result = "".join(r)
print result
The same code can be written in D2:
import std.stdio, std.algorithm, std.conv, std.range, std.string;
void main() {
auto r = map!("to!string(a)")(iota(20));
//string result = join(array(r), ""); // OK
string result = join(r, ""); // error
writeln(result);
}
But I'd like a std.string.join() able to accept a Range too, so I can use
join(r, "") instead of join(array(r), ""), because it's shorter, simpler,
natural enough and reduces memory used (and probably increases code performance
too).
When the total size of the resulting string is not known because the input is a
lazy sequence of strings, then probably join() has to use something like
appender() to improve its performance.
--
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
