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digitalmars.D.bugs - [Issue 5530] New: std.algorithm.len()


           Summary: std.algorithm.len()
           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 2011-02-05 17:22:30 PST ---
A simple task asks to sort an array according to the length of its items. This
is a D2 solution:

import std.stdio, std.algorithm;
void main() {
    auto l =
    schwartzSort!((s){return s.length; })(l);

It's supposed to print:
[['o'], ['d', 'e'], ['m', 'n'], ['a', 'b', 'c'], ['f', 'g', 'h'], ['i', 'j',
'k', 'l']]

I suggest to add a simple len() function to std.algorithm, that allows to
shorten that very common code (mapping lengths is a very common operation):

import std.stdio, std.algorithm;
size_t len(Range)(Range r) if (is(typeof(r.length))) {
    return r.length;
void main() {
    auto l =

In Python the "len()" function is a free function to allow it to be used as
mapping function, sorting function for a Schwartz sort, etc. In Ruby there is a
"size" standard attribute, and blocks are more used.

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