Rails 4 - passing variable to partial

Question

I am following the Ruby on Rails tutorial and have come across a problem while trying to pass variables to partials   My  user partial is as follows   lt li gt     lt    gravatar for user  size  52   gt     lt    link to user name  user   gt   lt  li gt    I would like to pass in a number for the size value  I am trying as follows without any luck    lt    render  users   locals   gt    size   gt  30    gt

User · Accepted Answer

You need the full render partial syntax if you are passing locals

<%= render @users, :locals => {:size => 30} %>

Becomes

<%= render :partial => 'users', :collection => @users, :locals => {:size => 30} %>

Or to use the new hash syntax

<%= render partial: 'users', collection: @users, locals: {size: 30} %>

Which I think is much more readable

User · Answer

From the Rails api on PartialRender      Rendering the default case      If you re not going to be using any of the options like collections or layouts  you can also use the short-hand defaults of render to render partials    Examples     Instead of  lt    render partial   account    gt   lt    render  account    gt     Instead of  lt    render partial   account   locals    account   buyer     gt   lt    render  account   account   buyer   gt      account to partial path returns  accounts account   so it can be used to replace     lt    render partial   accounts account   locals    account   account    gt   lt    render  account   gt      posts is an array of Post instances  so every post record returns  posts post  on  to partial path     that s why we can replace     lt    render partial   posts post   collection   posts   gt   lt    render  posts   gt    So  you can use pass a local variable size to render as follows    lt    render  users  size  50   gt    and then use it in the  user html erb partial    lt li gt       lt    gravatar for user  size  size   gt       lt    link to user name  user   gt   lt  li gt    Note that size  size is equivalent to  size   gt  size

User · Answer

Don t use locals in Rails 4 2   In Rails 4 2 I had to remove the locals part and just use size  30 instead  Otherwise  it wouldn t pass the local variable correctly   For example  use this     lt    render  users  size  30   gt

User · Answer

If you are using JavaScript to render then use escape JavaScript   lt   render partial  partial name  locals  gt   newval  gt  oldval   gt

User · Answer

Either  render partial   user   locals   size  30    Or  render  user   size  30   To use locals  you need partial  Without the partial argument  you can just list variables directly  not within locals

User · Answer

Syntactically a little different but it looks cleaner in my opinion   render  my partial   locals    title   My awesome title       not a big fan of the arrow key syntax render  my partial    locals   gt     title   gt   My awesome title

User · Answer

ou are able to create local variables once you call the render function on a partial  therefore if you want to customize a partial you can for example render the partial  form html erb by    lt    render  form   button label   Create New Event   url  new event url   gt   lt    render  form   button label   Update Event   url  edit event url   gt    this way you can access in the partial to the label for the button and the URL  those are different if you try to create or update a record  finally  for accessing to this local variables you have to put in your code local assigns  button label   local assigns  name of your variable     lt   form for  event  url  local assigns  url   do  f     gt   lt    render  shared error messages events    gt   lt    f label  title   Title   gt     lt    f text field  title  class   form-control   gt     lt   f label  date   Date   gt     lt   f date field  date  class   form-control     gt     lt   f label  description   Description   gt     lt   f text area  description  class   form-control     gt     lt    f submit local assigns  button label   class  btn btn-primary   gt   lt  end  gt

[ruby-on-rails] Rails 4 - passing variable to partial

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