Very basic question

Rails
1

I know this may be a very basic question, but confusing me.

If I write the following for example in the controller:

@x = App.new(params[:x])

I know that I’m trying to create a new object here, but how can I read
the params[:x] part.

I know also that “params” is a Hash table in the controller, but what is
the following statement trying to say when passing [:x] to params? What
is this value?
From where will I retrieve it?

Thanks.

2

SW Engineer wrote:

I know this may be a very basic question, but confusing me.

If I write the following for example in the controller:

@x = App.new(params[:x])

I know that I’m trying to create a new object here, but how can I read
the params[:x] part.

I know also that “params” is a Hash table in the controller, but what is
the following statement trying to say when passing [:x] to params? What
is this value?
From where will I retrieve it?

Do you understand how hashes (not “Hash tables”!) work in Ruby? If not,
go read the Pickaxe book or other basic reference, then come back if you
have further questions.

Or are you asking where the params hash gets assigned to in the first
place? If so, then that’s done by the Rails framework. I believe the
Rails Guides will tell you more about that.

Thanks.

Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]

3

Thanks @Marnen.

I’m asking just how to read this:

@x = App.new(params[:x])

Like saying, “Create a new object…”.

4

On 27 September 2010 21:49, SW Engineer [email protected] wrote:

Thanks @Marnen.

I’m asking just how to read this:

@x = App.new(params[:x])

Like saying, “Create a new object…”.

Create a new App object, passing params[:x] to the initialize method.
As Marnen said this is very basic Ruby. Get the Pickaxe book and work
through it.

Colin

5

Thanks a lot.

6

On Sep 27, 9:49 pm, SW Engineer [email protected] wrote:

Thanks @Marnen.

I’m asking just how to read this:

@x = App.new(params[:x])

params[:x] means (assuming that params is a Hash) get the value for
the key :x

Fred

7

Please quote when replying.

SW Engineer wrote:

Thanks @Marnen.

I’m asking just how to read this:

@x = App.new(params[:x])

Like saying, “Create a new object…”.

And I pointed you to where you can find the answers. Was the
information in those sources insufficient? If so, what part is still
problematic for you?

Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]

8

Thanks @Fred.

Now, I’m getting it better.

The last thing is, will the value be passed as a parameter to [:x] when
creating a new object?

9

On 27 September 2010 22:10, SW Engineer [email protected] wrote:

Thanks @Fred.

Now, I’m getting it better.

The last thing is, will the value be passed as a parameter to [:x] when
creating a new object?

Please go and read up on Ruby and go through some basic Ruby
tutorials. Then you will look back on the question you asked and be
embarrassed that every time someone googles and comes across it they
will think how silly it is.

Colin

10

On Sep 27, 5:10 pm, SW Engineer [email protected] wrote:

Thanks @Fred.

Now, I’m getting it better.

The last thing is, will the value be passed as a parameter to [:x] when
creating a new object?

Posted viahttp://www.ruby-forum.com/.

This is both Rails basics and Ruby basics. ‘params’ is a hash and acts
like a hash. Here is a quick example from the console that I hope
helps but you would actually save time and learn more by reading up on
the subject:

params = {}
=> {}
params.class
=> Hash
params[:x] = ‘SW Engineer’
=> “SW Engineer”
params.inspect
=> “{:x=>"SW Engineer"}”
puts params[:x]
SW Engineer

As you can see ‘:x’ is the key to the value ‘SW Engineer’. In Rails
that value would be coming from a field in your page called ‘x’.