• dsmith (5/5) Nov 23 2012 What is the best way to have a function sort an associative array
• Andrej Mitrovic (9/14) Nov 23 2012 Hashes are unordered, you can't sort them by key because they don't
• Timon Gehr (12/17) Nov 23 2012 A hash table is unsorted by definition. What is it that you want to do
• dsmith (4/25) Nov 23 2012 Suppose the string is of the format 201207, 21208, ...
• Timon Gehr (2/30) Nov 23 2012 tpl[0] is the key and tpl[1] is the value in this case.

"dsmith" <ds nomail.com> writes:

What is the best way to have a function sort an associative array 
by key?  The following yields a conversion error.

double[string] aa_sort(double[string] aa) {
   return aa.keys.sort;
}

Andrej Mitrovic <andrej.mitrovich gmail.com> writes:

On 11/23/12, dsmith <ds nomail.com> wrote:
 What is the best way to have a function sort an associative array
 by key?  The following yields a conversion error.

 double[string] aa_sort(double[string] aa) {
    return aa.keys.sort;
 }

Hashes are unordered, you can't sort them by key because they don't
preserve any order during insertion/removal. You can alternatively
return a sorted array:

string[] keys_sorted(double[string] aa) {
    string[] keys = aa.keys;
    sort(keys);  // from std.algorithm;
    return keys;
}

Timon Gehr <timon.gehr gmx.ch> writes:

On 11/23/2012 07:09 PM, dsmith wrote:
 What is the best way to have a function sort an associative array by
 key?  The following yields a conversion error.

 double[string] aa_sort(double[string] aa) {
    return aa.keys.sort;
 }

A hash table is unsorted by definition. What is it that you want to do 
exactly?

The following will generate a newly allocated dynamic array of key-value 
pairs, sorted by key:

import std.algorithm, std.typecons;

Tuple!(string, double)[] aa_sort(double[string] aa){
     typeof(return) r=[];
     foreach(k,v;aa) r~=tuple(k,v);
     sort!q{a[0]<b[0]}(r);
     return r;
}

"dsmith" <ds nomail.com> writes:

On Friday, 23 November 2012 at 18:24:07 UTC, Timon Gehr wrote:
 On 11/23/2012 07:09 PM, dsmith wrote:
 What is the best way to have a function sort an associative 
 array by
 key?  The following yields a conversion error.

 double[string] aa_sort(double[string] aa) {
   return aa.keys.sort;
 }

 A hash table is unsorted by definition. What is it that you 
 want to do exactly?

 The following will generate a newly allocated dynamic array of 
 key-value pairs, sorted by key:

 import std.algorithm, std.typecons;

 Tuple!(string, double)[] aa_sort(double[string] aa){
     typeof(return) r=[];
     foreach(k,v;aa) r~=tuple(k,v);
     sort!q{a[0]<b[0]}(r);
     return r;
 }

Suppose the string is of the format 201207, 21208, ...
So aa["201207"] == 123.45

How do you parse the tuple for the key and the value?

Timon Gehr <timon.gehr gmx.ch> writes:

On 11/23/2012 07:48 PM, dsmith wrote:
 On Friday, 23 November 2012 at 18:24:07 UTC, Timon Gehr wrote:
 On 11/23/2012 07:09 PM, dsmith wrote:
 What is the best way to have a function sort an associative array by
 key?  The following yields a conversion error.

 double[string] aa_sort(double[string] aa) {
   return aa.keys.sort;
 }

 A hash table is unsorted by definition. What is it that you want to do
 exactly?

 The following will generate a newly allocated dynamic array of
 key-value pairs, sorted by key:

 import std.algorithm, std.typecons;

 Tuple!(string, double)[] aa_sort(double[string] aa){
     typeof(return) r=[];
     foreach(k,v;aa) r~=tuple(k,v);
     sort!q{a[0]<b[0]}(r);
     return r;
 }

 Suppose the string is of the format 201207, 21208, ...
 So aa["201207"] == 123.45

 How do you parse the tuple for the key and the value?

tpl[0] is the key and tpl[1] is the value in this case.