💌 params[]: Direct from the user
- Comes from the request itself: URL segments (
:id), query strings (?foo=bar), or form data. - You use it in the same route where the request is made.
- It's like checking the envelope of a letter to see who it's from. It's raw input.
Example:
params[:id] # from `/blog/42`
params[:search] # from `/search?search=cats`
💅 @instance_variable: For sharing across templates
- Used to pass data to views (templates), or between routes if you're being fancy.
- You set it in the route/controller action and access it in the view (
erb,haml, whatever). - It’s like putting your lipstick on the table for others to use. You're saying, "Here, this is for the next part."
Example:
@article = fetch_api(...)
# later in the view: <%= @article['title'] %>
💡 Rule of Thumb
- Use
params[]to get data from the request. - Use
@variablesto send data to the view or carry stuff along in your code. - Always guard against
nilwhen dealing with external data. They're like unreliable exes — might show up, might ghost you.
If you ever get confused again, just ask yourself:
“Is this coming from the outside world? Or is this something I already put on the shelf for later?”