# Quick question about @params **URL:** \ **Category:** Rails\ **Created:** [March 4, 2006, 12:53am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412 "2006-03-04T00:53:22Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Daniel\_Teng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@Daniel\_Teng](https://www.ruby-forum.com/u/Daniel_Teng)\ **Post date:** [March 4, 2006, 12:53am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412/1 "2006-03-04T00:53:22Z")
I was looking through the loginGenerator code and noticed the following: Login: User.authenticate(@params[:user\_login], @params[:user\_password]) Signup User.authenticate(@user.login, @params[:user][:password]) The syntax of the call in the signup code confused me…what exactly does @params[:user][:password] this return to me? Is the params structure a multi-dimensional array? I would have thought that the login and signup use of params would be the same. Thanks in advance ---
**Author:** ![Daniel\_Teng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@Daniel\_Teng](https://www.ruby-forum.com/u/Daniel_Teng)\ **Post date:** [March 4, 2006, 1:49am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412/2 "2006-03-04T01:49:53Z")
Daniel Teng wrote: > I was looking through the loginGenerator code and noticed the following: > > Login: > User.authenticate(@params[:user\_login], @params[:user\_password]) > > Signup > User.authenticate(@user.login, @params[:user][:password]) > > The syntax of the call in the signup code confused me…what exactly > does @params[:user][:password] this return to me? Is the params > structure a multi-dimensional array? I would have thought that the > login and signup use of params would be the same. > > Thanks in advance @params[:user][:password] is a hash within a hash. It says, get me the value for password in the user hash. I am not very familiar with the specific example in the LoginGenerator code. @params[:user\_login] is going to return you the value for the key :user\_login in the @params hash. Gareth ---
**Author:** ![Daniel\_Teng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@Daniel\_Teng](https://www.ruby-forum.com/u/Daniel_Teng)\ **Post date:** [March 5, 2006, 6:37am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412/3 "2006-03-05T06:37:32Z")
Thanks! I was a bit confused, being a newcomer to the environment, when I expected the syntax to read something more like: @user = @params[:user] @password = @user.password I didn’t realize that the password was represented as a hash within the user object. Regards Daniel ---
**Author:** ![Daniel\_Teng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@Daniel\_Teng](https://www.ruby-forum.com/u/Daniel_Teng)\ **Post date:** [March 5, 2006, 8:10am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412/4 "2006-03-05T08:10:52Z")
Daniel Teng wrote: > Thanks! I was a bit confused, being a newcomer to the environment, when > I expected the syntax to read something more like: > > @user = @params[:user] > @password = @user.password > > I didn’t realize that the password was represented as a hash within the > user object. I wouldn’t say “the password was represented as a hash within the user object”. The password’s not a hash, it’s a field within user. But, if you look at the generated html for your login page, you’ll see that the “name” attribute on the input tag for your password field is “user[password]”. That notation tells rails to create a hash under the key “user” in the params hash. In that hash, there are string values under keys like “password”, “login”, etc. These are the values that are going to go in the user object. So, that notation is a way of grouping together the input params that are going to go into some model object. And, it allows one to say things like “User.new(@params[:user])” because that’ll pass everything in the “user” param hash into the constructor (which can be a little dangerous btw… someone can start playing around with submitting “user[something]” combinations…). And in the case you were looking at, the password was submitted as user[password], so rails puts that in a :user hash, so you need to do @params[:user][:password] to get the user hash and then the value for password within that. Hope that makes things a little clearer. b ---
**Author:** ![Daniel\_Teng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@Daniel\_Teng](https://www.ruby-forum.com/u/Daniel_Teng)\ **Post date:** [March 7, 2006, 1:04am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412/5 "2006-03-07T01:04:56Z")
That was a great detailed explanation of how it works. Is this behavior documented somewhere in the official guides? I’d like to know where I can read up on this before posting to the group. Daniel ---
**Author:** ![Daniel\_Teng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@Daniel\_Teng](https://www.ruby-forum.com/u/Daniel_Teng)\ **Post date:** [March 7, 2006, 6:31am UTC](https://www.ruby-forum.com/t/quick-question-about-params/54412/6 "2006-03-07T06:31:06Z")
Well, I hate to tell you to buy a book, but Agile Web D. with Rails is pretty indispensible when you’re starting out (and I’m just barely past that). The first chapter is pretty hand-holding, though I don’t know that it gets into the params stuff. I have that and the “Pickaxe” book (Programming Ruby, also by Dave T.). I gave myself the time to read large chunks of these and played with examples and it started to gel. Sorry if that’s not the most helpful answer… but you just have to give yourself some time. That and ask questions here… it’s great to have this active a list! b