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April 06, 2012 [Issue 7839] New: std.range.count() too | ||||
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http://d.puremagic.com/issues/show_bug.cgi?id=7839 Summary: std.range.count() too Product: D Version: D2 Platform: All OS/Version: All Status: NEW Severity: enhancement Priority: P2 Component: Phobos AssignedTo: nobody@puremagic.com ReportedBy: bearophile_hugs@eml.cc --- Comment #0 from bearophile_hugs@eml.cc 2012-04-05 17:59:57 PDT --- I'd like a count() in std.range. It's similar to the generator with the same name in the Python itertools module: http://docs.python.org/library/itertools.html#itertools.count a count() is also useful with bigints, where you can't replace it with iota(BigInt.max). A bare-bones implementation that shows it basic semantics (but it's useful to add few more methods): struct Count(T) { T n; this(T n_) { this.n = n_; } const bool empty = false; @property T front() { return n; } void popFront() { /* n++; */ n += 1; } } // Two helper functions Count!T count(T)(T start) { return Count!T(start); } Count!T count(T)() { return Count!T(cast(T)0); } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
April 23, 2012 [Issue 7839] std.range.count() too | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=7839 --- Comment #1 from bearophile_hugs@eml.cc 2012-04-23 13:54:31 PDT --- And answer to a question by jerro in D.learn: http://forum.dlang.org/thread/4F949E90.9060700@webdrake.net#post-evdrwckxsqieyrweuxzp:40forum.dlang.org > Couldn't it just be iota with no parameters? The Count range has a helper count() function similar to this, that's meant to have an argument that defaults to zero: Count!T count(T)(T start=0) if (isIntegral!T) { return Count!T(start); } The argument allows it to start from another starting point, and it allows you to specify the type of the numbers it yields, while in iota() without arguments it's less easy to specify the type of the numbers it yields. Count(5) is easy to replace with iota(5, int.max), but count(BigInt(0)) is less easy to replace with iota, because it doesn't give you a way to denote a right-open BigInt interval. And using iota(BigInt(0), BigInt(ulong.max)) is not that good. Currently using BigInt in iota seems to not even being supported. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
April 25, 2012 [Issue 7839] std.range.count() too | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=7839 --- Comment #2 from bearophile_hugs@eml.cc 2012-04-24 19:43:36 PDT --- std.algorithm has a function named count(), so this range will need a different name. Maybe countFrom()? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
April 25, 2012 [Issue 7839] std.range.countFrom() too | ||||
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Posted in reply to bearophile_hugs@eml.cc | http://d.puremagic.com/issues/show_bug.cgi?id=7839 bearophile_hugs@eml.cc changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|std.range.count() too |std.range.countFrom() too --- Comment #3 from bearophile_hugs@eml.cc 2012-04-24 19:47:13 PDT --- Changed the name of this issue from "std.range.count() too" to "std.range.countFrom() too". -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
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