How to evaluate the contents of an each loop - erb

Question

Here's the setup:
I have a data folder full of yaml files, each of which contains metadata about a post. In my .erb template, I'm looping through all of these with a simple each.do loop.
Now, what I want to do, rather than print every yaml file in that folder, is to only print those where the .yaml content contains an exact string.
Is this possible?
--
For example, let's say I have this structure for data
-data
--blogposts
---post1.yaml
---post2.yaml
...
---post100.yaml
and then, for each post#.yaml, for sake of simplicity, let's say it looks like this:
---
:id: 1
:title: my example title
:postCategory:
- :id: 1
:categoryTitle:
:Business
And in my template, the loop to grab ALL posts obviously looks like:
<% data.blogposts.each do |id, post| %>
*display stuff*
<% end %>
What I really want is to evaluate each .yaml file within "blogposts", check to see if there is a categoryTitle item that matches a string (let's say Business here), and if so, output as an item in the loop. The goal is that I could use this on each "category page" and dynamically just pull in posts who's category is being requested.

Answer 1

Use Enumerable#grep, for given category
<% data.blogposts.each do |id, post| %>
if File.readlines("#{post.name}.yaml").grep(/#{category}/).size > 0
*display stuff*
end
<% end %>

Answer 2

I will go with something like this:
Check the yaml file when i receive it and search for categoryTitle.
Add the file name to a master.yaml file.
Read master.yaml to get the file name of all files i want to display.
This way you don't loop every time in all your files, you just go through one file to identify the ones that you really need to open.
So your folder structure will have one more file, for example:
-data
--master.yaml
--blogposts
---post1.yaml
---post2.yaml
...
---post100.yaml
And the master.yaml file structure may look like this:
:business:
:post1.yaml
:post3.yaml
:othertitle:
:post2.yaml
:post5.yaml
Just check master.yaml for the files with the title you want (e.g. business) and loop through those files only (instead of looping all files every time).