From: Gareth Adams <gareth.adams@...>
Date: 2006-09-27T08:29:48+09:00
Subject: Re: Accessing Nested Hashes Directly

atraver <at> gmail.com <atraver <at> gmail.com> writes:

> However, sometimes the "name" element might not come over the wire
> (through no fault of Ruby's nor Rails' -- it's just a problem we have
> to deal with in our system). In this case, Ruby will throw a
> NoMethodError on nil.[] because we tried to access the value at "given"
> on an element that does not exist. Furthermore, sometimes the "user"
> element does not exist, either! This led me to code that looks like
> this:
> 
>   if params["body"]["user"]
>     if params["body"]["user"]["name"]
>       first_name = params["body"]["user"]["name"]["given"]
>     end
>   end
> 
> That's not very elegant when you're doing it with many (15 - 30)
> fields. 

I use something like the following, although it would also look unweildy when
chained together a lot

hsh.fetch(:key, {}) # returns either hsh[:key], or {} if !hsh.has_key?(:key)

so

hsh.fetch(:key1, {}).fetch(:key2, nil) # will work as expected, silently
returning nil on error

Gareth