Brad Wilson <[EMAIL PROTECTED]> wrote:
> Dictionaries of identical size with identical items will enumerate
> identically.
That's not true. The common strategies that hash tables use to resolve
conflicts, i.e. chaining, re-hashing and probing, all have dependencies
on the order of insertion. For example, the following program prints out
two different sequences:
---8<---
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
class App
{
static void Main()
{
Dictionary<string,int> dict = new Dictionary<string,int>();
// Add in order
for (int i = 1; i <= 10; ++i)
dict.Add(i.ToString(), i);
Console.WriteLine(ToString(dict, ", "));
// Add in reverse order
dict.Clear();
for (int i = 10; i >= 1; --i)
dict.Add(i.ToString(), i);
Console.WriteLine(ToString(dict, ", "));
}
static string ToString(IEnumerable items, string separator)
{
StringBuilder result = new StringBuilder();
foreach (object item in items)
result.Append(item).Append(separator);
if (result.Length > 0)
result.Length -= separator.Length;
return result.ToString();
}
}
--->8---
-- Barry
--
http://barrkel.blogspot.com/
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