2

I'm trying to flatten an array for my form.

def update
  @tour = Tour.find(params[:id])
  params[:tour][:hotel_ids][0] = params[:tour][:hotel_ids][0].split(',')
...

This results in:

"hotel_ids"=>[["1","2"]]

Naturally I want it to be 

"hotel_ids"=>["1","2"]

My Form:

<%= text_field_tag 'tour[hotel_ids][]', nil %>

Hope anyone can help with this.

EDIT

I've gotten it to work, somehow. This might be a bad way to do it though:

I changed the text_field that get's the array from jquery to:

<%= text_field_tag 'tour[h_ids][]', nil %>

then in my controller I did:

params[:tour][:hotel_ids] = params[:tour][:h_ids][0].split(',')

And this works, I had to add h_ids to attr_accessor though. And it will probably be a big WTF for anyone reading the coder later... but is this acceptable?

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5
  • So params[:tour][:hotel_ids] = params[:tour][:hotel_ids][0].split(',') did not work? Because that is EXACTLY what you are doing there, but without the buffer object. Commented Aug 9, 2010 at 2:14
  • Nope, it did not work... Commented Aug 9, 2010 at 2:32
  • Btw, big thanks to you Rock and MBO for bearing with me. It's a huge relief to at least have it working after literally days of trying different things. Commented Aug 9, 2010 at 2:53
  • No Problem. The famous »params-Hash« is really nasty sometimes ;-) Glad to hear that the problem is now solved :-) Commented Aug 9, 2010 at 2:59
  • In StackOverflow you can also answer your own question and mark it as accepted (you won't get points for this) if you found another solution for your own question :-) Commented Aug 9, 2010 at 18:20

2 Answers 2

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4

This is ruby! 

params[:tour][:hotel_ids][0].flatten!

should do the trick!

ps: the '!' is important here, as it causes the 'flatten' to be saved to the calling object.

pps: for those ruby-related questions I strongly suggest experimenting with the irb or script/console. You can take your object and ask for

object.inspect
object.methods
object.class

This is really useful when debugging and discovering what ruby can do for you.

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10 Comments

I've been experimenting a lot in irb before posting, but my issue is how to make it work in rails. Let's say params[:tour][:hotel_ids][0] == ["1","2","3"] then calling flatten on that won't do anything. What I really need to be calling flatten on is the hotel_ids parameter. Hope this clarifies.
params[:tour][:hotel_ids].flatten! does not work then? Dont forget the '!' What does params[:tour][:hotel_ids].class .inspect return? Or try a buffer: buf = params[:tour][:hotel_ids][0] # or without the [0] buf.flatten! And check if thats what you want.
wait. What is params[:tour][hotel_ids][0] exactly? Do you need to call split(',') to get an Array in the first place? Then maybe just append the .flatten (without the '!') to params[:tour][:hotel_ids][0] = params[:tour][:hotel_ids][0].split(',').
params[:tour][hotel_ids][0] is an array I get from jquery. the value is ["1,3"], but since rails require the objects to strings I use split to create ["1","3"].
and after the split you get this double array [["1","3"]]? Then the flatten should work on this. params[:tour][:hotel_ids][0] = params[:tour][:hotel_ids][0].split(',').flatten should give you ["1","3"] then.
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0

Simply use <%= text_field_tag 'tour[hotel_ids]', nil %> here, and then split like you do in example.

What really happens in your example is that Rails get param(-s) tour[hotel_ids][] in request and it thinks: "ok, so params[:tour][:hotel_ids] is an array, so I'll just push every value with this name as next values to this array", and you get exactly this behavior, you have one element in params[:tour][:hotel_ids] array, which is your value ("1,2"). If you don't need (or don't want) to assign multiple values to same param then don't create array (don't add [] at the end of the name)

Edit:

You can also go easy way (if you only want answer to posted question, not solution to problem why you have now what you expect) and just change your line in controller to:

params[:tour][:hotel_ids] = params[:tour][:hotel_ids][0].split(',')

#split returns array and in your example you assigned this new array to first position of another array. That's why you had array-in-array.

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3 Comments

That was my initial idea as well, but the result came out "hotel_ids"=>"1,2". I want the hotel_ids to be an array of multiple objects collected from params[:tour][:hotel_ids][]
@Amund If you want multiple objects then you need multiple <input>'s in your html (or input with multiple=true), otherwise you have to create that multiple objects by yourself, with split(",") for example
Should I also have a hidden field with <%= hidden_field_tag 'tour[hotel_ids]', nil %> ? I tried with just altering the controller but the result was: "hotel_ids"=>["1,3"] yet inspect on params[:tour][:hotel_ids] == ["1", "3"] When I tried with a hidden_field I got Status: 500 Internal Server Error expected Array (got String) for param `hotel_ids'

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