Error of undefined method

luislavena · June 20, 2011, 6:34pm

Hi all, I have very basic error that i have no idea how to show

I have user table
id
name
add
phone number

then i select all in user table
using => @users = User.all

=> @users.name

it gives me undefined method name Array<…>

Please give me some advice…

Thanks

Yennie · June 20, 2011, 6:40pm

Hi!

The method User.all returns an Array of users, not a single user.

I think you have to iterate over the array, using each.

@users.each { |u| u.name }

Everaldo

Yennie · June 20, 2011, 6:40pm

@users.all basically returns “array” of users

so you have to iterate through this array

@users.each do |user|
puts user.name
end

tom

On Jun 20, 2011, at 18:33 , Yennie wrote:

using => @users = User.all

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Yennie · June 20, 2011, 6:50pm

thanks

On Mon, Jun 20, 2011 at 12:38 PM, Everaldo G.
[email protected]wrote:

Thanks

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Yennie · June 20, 2011, 8:43pm

On 20 June 2011 17:53, joanne ta [email protected] wrote:

and it causes undefined method image
What does it say has not got a method image? It is always a good idea
to post the complete error message (use copy/paste rather than
re-typing it). If it says the nil has not got the method then your
call of Picture.where has not found a record.

Colin

Yennie · June 20, 2011, 6:55pm

I have other undefined method when i combine the code above together

<%@users = User.all%>
<[email protected] do |u|%>
<%u.culture_id%>

<% @pic= Picture.where(:phrase_id => :route , :culture_id =>
u.culture_id).first%>
My picture <%= @pic.image%>

and it causes undefined method image

please give me advices… thank you so much

Joanne

On Mon, Jun 20, 2011 at 12:48 PM, joanne ta [email protected]
wrote:

id
it gives me undefined method name Array<…>

Please give me some advice…

Thanks

Joanne

Yennie · June 20, 2011, 9:09pm

the error is undefined method `image’ for nil:NilClass

On Mon, Jun 20, 2011 at 2:42 PM, Colin L. [email protected]
wrote:

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Yennie · June 20, 2011, 9:35pm

You don’t have an <% end %> to close the <% @users.each %> block in the
code
you included, so my guess is that your u variable is already out of
scope by
the time you call u.image.

Yennie · June 21, 2011, 10:13am

Hi,

Few things here:

Would be good if you can paste full code from the beginning of the
loop
till the place where you render picture
It is not a good practice to set instance variables in the views, set
them in controller instead
It is not a good practice to do finds in views, if you want to fetch
a
picture for the user, it’s better to define a relationship between
picture
and user models. And then do something like this in the controller -
@users
= User.includes(:picture).all

Hope this helps.

Yennie · June 21, 2011, 9:25am

On 20 June 2011 20:08, joanne ta [email protected] wrote:

Please don’t top post, it makes it difficult to follow the thread.
Insert your reply at appropriate places in previous message. Thanks.

the error is undefined method `image’ for nil:NilClass

So what does that mean (see my previous post)?

Colin

Yennie · June 21, 2011, 3:53pm

end
<% end %>

error is

You have a nil object when you didn’t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.each

Extracted source (around line #79):

76:

77: <%= image_tag url_for(:controller => “/users”, :action =>
“index”),
:width => “25px”, :height => “25px”%>
78:
79: <[email protected] do |c|%>
80: <%= c.image%>
81: <% end %>
82:

please give me some advices…

Yennie · June 21, 2011, 3:48pm

My controller:

def index
@users= User.all

@users.each do |p|
@pic= Picture.where(:phrase_id => :route , :culture_id =>

p.culture_id).first
send_data @pic.image, :type => ‘image/gif’, :disposition =>
‘inline’
end
end

in View

<%= image_tag url_for(:controller => "/users", :action => "index"), :width => "25px", :height => "25px"%>

<[email protected] do |c|%>
<%= c.image%>
<% end %>

please give me some advices…

thanks
Joanne

Yennie · June 21, 2011, 4:14pm

it does not work, it is complaining other error

NoMethodError (undefined method image' for [nil]:Array): app/controllers/patients_controller.rb:27:in block in index’
app/controllers/patients_controller.rb:25:in each' app/controllers/patients_controller.rb:25:in index’

On Tue, Jun 21, 2011 at 9:57 AM, Chirag S.
[email protected]wrote:

end
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Yennie · June 21, 2011, 3:59pm

Your index action should be something like this:

def index
@users= User.all
@pic = []

@users.each do |p|
@pic << Picture.where(:phrase_id => :route , :culture_id =>
p.culture_id).limit(1)
end
end

Yennie · June 21, 2011, 4:29pm

Oh yes… sorry about that.
I assumed that you will find picture for every query.

You can try this instead:
def index
@users= User.all
@pic = []

@users.each do |p|
@pic << Picture.where(:phrase_id => :route , :culture_id =>
p.culture_id).limit(1)
end
@pic.compact!
end

by calling compact! on the array, we will eliminate all nil object.

On another note, are you sure, this is what you want to do? If you have
100
users, it will fire 100 sql queries which is not good.

On Tue, Jun 21, 2011 at 7:42 PM, joanne ta [email protected] wrote:

end
For more options, visit this group at
Yen

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Yennie · June 21, 2011, 4:58pm

Can you paste what you have in your index method?
You should not be getting this error because we have already defined
@pic as
an empty array.

On Tue, Jun 21, 2011 at 8:10 PM, joanne ta [email protected] wrote:

@users= User.all

The error occurred while evaluating nil.compact!):

On Tue, Jun 21, 2011 at 7:42 PM, joanne ta [email protected] wrote:

On Tue, Jun 21, 2011 at 9:57 AM, Chirag S. <

p.culture_id).limit(1)
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Yennie · June 21, 2011, 4:42pm

On Tue, Jun 21, 2011 at 10:27 AM, Chirag S.
[email protected]wrote:

p.culture_id).limit(1)
end
@pic.compact!
end

by calling compact! on the array, we will eliminate all nil object.

On another note, are you sure, this is what you want to do? If you have 100
users, it will fire 100 sql queries which is not good.

Yes i think i have that problem as well because if i remove "@users.each
do |p| "
and then it will cause undefined method of culture_id…
plus when i call @pic.compact! , it gives me

NoMethodError (You have a nil object when you didn’t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.compact!):
app/controllers/patients_controller.rb:29:in `index’

what is mean? cuz i want to display picture on the browser too…

please help… thank you very much

Joanne

Yennie · June 21, 2011, 5:06pm

Can you paste what you have in your index method?

You should not be getting this error because we have already defined @pic
as an empty array.

@pic.compact!
p.culture_id).limit(1)
do |p| "
please help… thank you very much

app/controllers/patients_controller.rb:27:in `block in index’

def index
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Yennie · June 21, 2011, 5:30pm

Remove the send_data line, it isn’t required.
Can you check if there are any records in your pictures table? Right
now
it looks like it is returning nil.

On Tue, Jun 21, 2011 at 8:35 PM, joanne ta [email protected] wrote:

send_data @pic.image, :type => 'image/png', :disposition => 'inline'
p.culture_id).limit(1)
do |p| "
please help… thank you very much

app/controllers/patients_controller.rb:27:in `block in index’

def index
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Yennie · June 21, 2011, 5:33pm

@users.each do |user|

An array of pictures doesn’t have an “image” attribute.

because i want to take a value “image” from Picture model
what can i do … I am really stuck now…

thanks

Joanne

Hassan S. ------------------------ [email protected]

twitter: @hassan

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