# Issue with variables in a partial view

**URL:** <https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719>\
**Category:** Rails\
**Created:** [September 4, 2007, 11:15am UTC](https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719 "2007-09-04T11:15:24Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![cmaxvv](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@cmaxvv](https://www.ruby-forum.com/u/cmaxvv)\
**Post date:** [September 4, 2007, 11:15am UTC](https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719/1 "2007-09-04T11:15:24Z")

</div>

I had a partial to display a list of ‘stories’, done in the traditional  
rails-tutorial kind of way - eg, an ‘article’ has a list of ‘stories’,  
so i have a partial called ‘story\_list’ that has this:

for story in @article.stories  
blah blah - some html and erb that works with ‘story’  
end

and i call it from the article’s show page with

Story list  
  
\<%= render :partial =\> ‘story/story\_list’ %\>

so far so standard, right? That all works fine.

However, in another place in my app i want to display a different set of  
stories (ones just done by the current user). To stay nice and DRY, i  
want to use just one partial to display the stories, whichever bunch of  
stories makes up the collection. So, i moved the start and end of the  
for loop out of the partial: now, the view page that calls the partial  
decides what makes up the collection, and the partial shows a single  
item. So now i have, in the calling view,

Story list  
  
for story in @article.stories  
\<%= render :partial =\> ‘story/story\_list’ %\>  
end

and the partial is now simply

blah blah - some html and erb that works with ‘story’

The problem is this: now, the partial doesn’t know what ‘story’ is - ie  
the local variable ‘story’ isn’t being passed through to the partial.  
But i thought that the partial was effectively pasted into the calling  
view page before being processed? In which case it shouldn’t matter?

I can get around this by passing through ‘@story’ instead of ‘story’,  
but i’d like to understand the problem rather than work around it. Can  
anyone explain? Is a partial call effectively a method call, so local  
vars won’t work, or something?

sorry for the long winded post…  
max

---

<div class="post-metadata">

**Author:** ![cmaxvv](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@cmaxvv](https://www.ruby-forum.com/u/cmaxvv)\
**Post date:** [September 4, 2007, 4:39pm UTC](https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719/2 "2007-09-04T16:39:45Z")

</div>

hi Max,

you can pass make a local variable available to partial by send it as  
part of :locals, like this

for story in @articles.stories  
\<%= render :partial =\> “story/story\_list”, :locals =\> { :story =\>  
story } %\>  
end

On Sep 4, 2:15 pm, Max W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

---

<div class="post-metadata">

**Author:** ![cmaxvv](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@cmaxvv](https://www.ruby-forum.com/u/cmaxvv)\
**Post date:** [September 4, 2007, 5:01pm UTC](https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719/3 "2007-09-04T17:01:54Z")

</div>

raghukumar wrote:

> hi Max,
> 
> you can pass make a local variable available to partial by send it as  
> part of :locals, like this
> 
> for story in @articles.stories  
> \<%= render :partial =\> “story/story\_list”, :locals =\> { :story =\>  
> story } %\>  
> end
> 
> On Sep 4, 2:15 pm, Max W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

Good tip, thanks!

---

<div class="post-metadata">

**Author:** ![cmaxvv](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@cmaxvv](https://www.ruby-forum.com/u/cmaxvv)\
**Post date:** [September 4, 2007, 5:19pm UTC](https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719/4 "2007-09-04T17:19:26Z")

</div>

Max W. wrote:

> I had a partial to display a list of ‘stories’, done in the traditional  
> rails-tutorial kind of way - eg, an ‘article’ has a list of ‘stories’,  
> so i have a partial called ‘story\_list’ that has this:
> 
> for story in @article.stories  
> blah blah - some html and erb that works with ‘story’  
> end
> 
> and i call it from the article’s show page with
> 
> Story list  
>   
> \<%= render :partial =\> ‘story/story\_list’ %\>
> 
> so far so standard, right? That all works fine.
> 
> However, in another place in my app i want to display a different set of  
> stories (ones just done by the current user). To stay nice and DRY, i  
> want to use just one partial to display the stories, whichever bunch of  
> stories makes up the collection. So, i moved the start and end of the  
> for loop out of the partial: now, the view page that calls the partial  
> decides what makes up the collection, and the partial shows a single  
> item. So now i have, in the calling view,
> 
> Story list  
>   
> for story in @article.stories  
> \<%= render :partial =\> ‘story/story\_list’ %\>  
> end
> 
> and the partial is now simply
> 
> blah blah - some html and erb that works with ‘story’
> 
> The problem is this: now, the partial doesn’t know what ‘story’ is - ie  
> the local variable ‘story’ isn’t being passed through to the partial.  
> But i thought that the partial was effectively pasted into the calling  
> view page before being processed? In which case it shouldn’t matter?
> 
> I can get around this by passing through ‘@story’ instead of ‘story’,  
> but i’d like to understand the problem rather than work around it. Can  
> anyone explain? Is a partial call effectively a method call, so local  
> vars won’t work, or something?

As this is a common pattern, Rails already has a built-in to do it  
easily. Once you have the partial for rendering an item in the story  
list, you can use it like so:

Story list  
  
\<%= render :partial =\> ‘story/story\_list’, :collection =\>  
@article.stories %\>

Take a look at the docs for render :partial.

–  
Josh S.  
[http://blog.hasmanythrough.com](http://blog.hasmanythrough.com)

---

<div class="post-metadata">

**Author:** ![cmaxvv](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@cmaxvv](https://www.ruby-forum.com/u/cmaxvv)\
**Post date:** [September 4, 2007, 5:46pm UTC](https://www.ruby-forum.com/t/issue-with-variables-in-a-partial-view/113719/5 "2007-09-04T17:46:47Z")

</div>

Josh S. wrote:

> As this is a common pattern, Rails already has a built-in to do it  
> easily. Once you have the partial for rendering an item in the story  
> list, you can use it like so:
> 
> Story list  
>   
> \<%= render :partial =\> ‘story/story\_list’, :collection =\>  
> @article.stories %\>
> 
> Take a look at the docs for render :partial.
> 
> –  
> Josh S.  
> [http://blog.hasmanythrough.com](http://blog.hasmanythrough.com)

ahh…that’s perfect, thanks. Looking at my copy of ‘agile web dev with  
ror’, i see it all explained nicely. Should have looked there first (as  
usual). 🙂

In case anyone else is looking at the above and thinking “but what are  
the individual items from the collection (that we’d normally call  
‘story’) called once we get into the partial?”, the answer is that it  
has the same name as the partial: so ideally i’d rename the partial to  
be called ‘\_story.rhtml’, and then i can just carry on using

blah blah - some html and erb that works with ‘story’

inside the partial.

thanks josh!