Problem about "each" in rails

CODE1:

<% @posts.each do |p|%>
<%=h p.name %>
<% end %>

this will show the name string like “Tom” in the web page.

CODE2:

<%=h @posts.each {|p| p.name} %>

why this code return serial strings like #Post:0x3a893e8 ?

On 18 March 2010 16:33, Grick Zh [email protected] wrote:

<%=h @posts.each {|p| p.name} %>

why this code return serial strings like #Post:0x3a893e8 ?

Because you’re outputting the return value of the whole loop, not the
output of each block.
If you run that command in your console, you will see it return an
array of Posts; and that’s what you’re trying to render.

If you want the names seperated by comma, try this:

<%=h @posts.map{|p| p.name}.join(’, ') %>

Michael P. wrote:

On 18 March 2010 16:33, Grick Zh [email protected] wrote:

<%=h @posts.each {|p| p.name} %>

why this code return serial strings like #Post:0x3a893e8 ?

Because you’re outputting the return value of the whole loop, not the
output of each block.
If you run that command in your console, you will see it return an
array of Posts; and that’s what you’re trying to render.

I got it,thanks for your help :slight_smile:

Adam S. wrote:

Or more concisely (because it’s fun):
<%=h @posts.map(&:name).to_sentence %>
which will make it “Tom, Dick, and Harry”.

I’m newbie,can’t understand “(&:name)”,but i know this code is skillful.

Or more concisely (because it’s fun):
<%=h @posts.map(&:name).to_sentence %>
which will make it “Tom, Dick, and Harry”.

Grick Zh wrote:

Adam S. wrote:

Or more concisely (because it’s fun):
<%=h @posts.map(&:name).to_sentence %>
which will make it “Tom, Dick, and Harry”.

  1. @posts.map
    This will return a new enumerable, replacing each element of @posts with
    whatever the block says
  2. &:name
    Shortcut to indicate a block and a method. In this case, the method is
    :name (post.name)

Other example: [1,2,3,4].inject(:+) # Sum every element of the array.
Will of course fail if an element does not understand “+”.

  1. to_sentence
    We now have an array with names. “to_sentence” is, I believe, an
    activesupport method which joins the array into a string with commas,
    and adds "and " between the second to last and last item.

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