From: Robert Klemme <shortcutter@...>
Date: 2008-02-12T06:29:56+09:00
Subject: Re: Hash keys

On 11.02.2008 20:32, J. Cooper wrote:
> I ran into something I hadn't realized (common occurrence). Keying a
> hash with a symbol is not the same as using a string. I guess it makes
> sense, but I've seen it done both ways, and I had been always using
> symbols for my keys. But then I ran into an issue on loading an external
> YAML object into a hash, and didn't realize it was keyed with strings so
> I got errors the first time around.
> 
> So two questions:
> 1) What is the preferred method of keying hashes? Symbols, strings,
> other?

It depends: my personal convention is this: use symbols if the set of 
keys is limited and probably known beforehand; use strings if the data 
is read from an external resource (e.g. a file) and there could be 
arbitrary key values.

> 2) Is there a smooth way to handle hashes that may have been keyed in
> either fashion?

I do not think there is a smooth one size fits all way.  You could of 
course convert a Hash containing on set of keys to the other one.  I 
don't think it is worthwhile though and haven't seen it so far.

Kind regards

	robert