Ruby Hash Querying

ruby-talk
1

Hello,
I am new to Ruby and have run into a small snag. I have a hash like
so:

@documentnames = {
  :finance_whitepaper => 'whitepaper one',
  :ecommerce_whitepaper => 'whitepaper two',
  :integratedsvs_datasheet => 'whitepaper three'
  }

So I am trying to then go like so:

@documentnames[k]

where k is a variable in a loop with the key from the has minus the
":" in front

But if I try to add the ":" in front

<%key = ':' + k%>

And then try to reference the element

<%= @documentnames[key] %>

I get a null value....

2

OK I answered my own question...sorry. But here is the answer in case
someone else asks the same silly question:

Use a string as a key (doh!)

@documentnames = {
   'finance_whitepaper' => 'whitepaper one',
   'ecommerce_whitepaper' => 'whitepaper two',
   'integratedsvs_datasheet' => 'whitepaper three'
  }

Problem solved!

···

On Jun 13, 11:30 am, kwest <kwes...@gmail.com> wrote:

Hello,
I am new to Ruby and have run into a small snag. I have a hash like
so:

@documentnames = {
  :finance_whitepaper => 'whitepaper one',
  :ecommerce_whitepaper => 'whitepaper two',
  :integratedsvs_datasheet => 'whitepaper three'
  }

So I am trying to then go like so:

@documentnames[k]

where k is a variable in a loop with the key from the has minus the
":" in front

But if I try to add the ":" in front

<%key = ':' + k%>

And then try to reference the element

<%= @documentnames[key] %>

I get a null value....

3

That happens because the keys are symbols, and not strings starting
with ":". Try either using strings instead of symbols as hash keys
(i.e., 'finance_whitepaper' rather than :finance_whitepaper - note que
quotes) or using k.to_sym inside the loop.

···

On 6/13/07, kwest <kwestin@gmail.com> wrote:

Hello,
I am new to Ruby and have run into a small snag. I have a hash like
so:

@documentnames = {
  :finance_whitepaper => 'whitepaper one',
  :ecommerce_whitepaper => 'whitepaper two',
  :integratedsvs_datasheet => 'whitepaper three'
  }

So I am trying to then go like so:

@documentnames[k]

where k is a variable in a loop with the key from the has minus the
":" in front

But if I try to add the ":" in front

<%key = ':' + k%>

And then try to reference the element

<%= @documentnames[key] %>

I get a null value....

--
Bira

http://sinfoniaferida.blogspot.com

4

kwest schrieb:

Hello,
I am new to Ruby and have run into a small snag. I have a hash like
so:

@documentnames = {
  :finance_whitepaper => 'whitepaper one',
  :ecommerce_whitepaper => 'whitepaper two',
  :integratedsvs_datasheet => 'whitepaper three'
  }

So I am trying to then go like so:

@documentnames[k]

where k is a variable in a loop with the key from the has minus the
":" in front

But if I try to add the ":" in front

<%key = ':' + k%>

And then try to reference the element

<%= @documentnames[key] %>

I get a null value....

The ":whatever" is a Ruby-Symbol, and you're trying to kinda "fake" it with a String. However, the answer is really easy, just use:
@documentnames[k.to_sym]

5

Great thank you. That is too easy. I am liking this.

···

On Jun 13, 11:36 am, Daniel Kempkens <Daniel.Kempk...@gmail.com> wrote:

kwest schrieb:

> Hello,
> I am new to Ruby and have run into a small snag. I have a hash like
> so:

> @documentnames = {
> :finance_whitepaper => 'whitepaper one',
> :ecommerce_whitepaper => 'whitepaper two',
> :integratedsvs_datasheet => 'whitepaper three'
> }

> So I am trying to then go like so:

> @documentnames[k]

> where k is a variable in a loop with the key from the has minus the
> ":" in front

> But if I try to add the ":" in front

> <%key = ':' + k%>

> And then try to reference the element

> <%= @documentnames[key] %>

> I get a null value....

The ":whatever" is a Ruby-Symbol, and you're trying to kinda "fake" it
with a String. However, the answer is really easy, just use:
@documentnames[k.to_sym]