Re: access hashmap objects

On Sat, Oct 1, 2011 at 3:28 PM, Sam s. <[e-mail]> wrote:
> I got objects inside of a hashmap. And they are packed as the following
> code says and I want to unpack them again to change their manipulate the
> data and pack it again in the same way. Or directly change each datum if
> that works.
>
> mutation_map =3D key =3D> {
> =A0 =A0 =A0 =A0 =A0column_family =3D> hash.collect{|k,v|
> _standard_insert_mutation(column_family, k, v, timestamp,
> options[:ttl])}
> =A0 =A0 =A0 =A0}

That's not a Hash but rather a partial description of how a Hash is created=
.

> def _standard_insert_mutation(column_family, column_name, value,
> timestamp, ttl =3D nil)
> =A0 =A0 =A0CassandraThrift::Mutation.new(
> =A0 =A0 =A0 =A0:column_or_supercolumn =3D>
> CassandraThrift::ColumnOrSuperColumn.new(
> =A0 =A0 =A0 =A0 =A0:column =3D> CassandraThrift::Column.new(
> =A0 =A0 =A0 =A0 =A0 =A0:name =A0 =A0 =A0=3D>
> column_name_class(column_family).new(column_name).to_s,
> =A0 =A0 =A0 =A0 =A0 =A0:value =A0 =A0 =3D> value,
> =A0 =A0 =A0 =A0 =A0 =A0:timestamp =3D> timestamp,
> =A0 =A0 =A0 =A0 =A0 =A0:ttl =A0 =A0 =A0 =3D> ttl
> =A0 =A0 =A0 =A0 =A0)
> =A0 =A0 =A0 =A0)
> Code from the fauna project on github. A ruby cassandra client.
>
> now I think I understand what happens in this bit of code, but if I have
> this mutation_map later in code and want to manipulate specific parts of
> it how would I do that.
> Like encrypting the whole map. I would need access to each bit and
> change it

A fairly simply way to do it would be to serialize it via Marshal and
encrypt the resulting binary sting.

> getting to the column_family I write mutation_map[key][column_family]
> How do I go from there? I have an object now and this object should have
> accessor methodes.
>
> I know java not as much about ruby. How do I access that data. Should
> simple for any ruby veteran but in all the tutorials they stick to such
> simple stuff that you don't learn this kind of things.

I am not sure what you are really up to.  Accessing members of a Hash
is fairly straightforward - for reading and writing.  You can easily
extend that to nested Hashes

irb(main):003:0> h=3D{:k =3D> {:j =3D> {}}}
=3D> {:k=3D>{:j=3D>{}}}
irb(main):004:0> h[:k][:j][:i] =3D 123
=3D> 123
irb(main):005:0> h
=3D> {:k=3D>{:j=3D>{:i=3D>123}}}

Kind regards

robert

--=20
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/