Ruby on Rails - Adding variable to params[]

Question

In the controller, how can I add a variable at the end of a params[]?

If I try this I get an error: params[:group_] + variable

How should it be done?

Edit per request

Ok, I have a form that sets groups of radio buttons with names like this:

group_01DRN0

Obviously I have different groups in the form (group_01AAI0, group_01AUI0, etc.) and the value is set according to the radio button selected within the group:

Radio button "group_01DRN0" could have value of "21" or "22" or "23", radio button "group_01AAI0" could have value of "21" or "22" or "23", etc.

In the DB I have every code (01DRN0, 01AAI0, 01AUI0, etc) so I want to select them from DB and iterate in the params value so I can get the radio button group value, I've tried this with no luck:

@codes=Code.get_codes
for c in @codes
  @all=params[:group_] + c.name
end

Thanks.

Your example code is over-writing @all with each loop iteration... — Larry K
– Larry K, Commented May 14, 2010 at 18:06

Hassen · Accepted Answer · 2012-08-29 14:49:55Z

4

p = params
p[:new_param_name] = new_param_value

It works for me (rails 3.2). Nota: using p instead of altering params avoids altering original parameters.

answered Aug 29, 2012 at 14:49

Hassen

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Comments

Larry K · Accepted Answer · 2010-05-14 18:01:15Z

3

params looks like a hash, but it really isn't. So if you need to "augment" params as you deal with the incoming data in your controller, invent a new data structure that includes either params or its members.

Added:

Maybe you're looking for

@codes=Code.get_codes
@all = []    
for c in @codes
  @all << params["group_#{c.name}"]
end

answered May 14, 2010 at 18:01

Larry K

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1 Comment

miligraf Over a year ago

I did not know you could use "group_#{c.name}" inside params[]! But that did the trick, thanks!

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