Another way to write: if some_variable && some_valiable.size == 2

Question

In Ruby and RoR, I often find that an object exists, that is, whether the properties of the object meet certain criteria. For instance:

if params[:id] && params[:id].size == 40
  ...do stuff
end

Is there a more efficient way to do this? Sort of:

if params[:id].size == 40 rescue false

but not using salvation?

Answer 1

With Rails 2.3, you can use the # method of object #:

if params[:id].try(:size) == 40
  # do stuff
end

try will return nil when nil is called (with any arguments). Hope this makes sense.

Answer 2

Try using andand gem:

require 'andand'

if params.andand.size == 40
  ...do stuff
end

Answer 3

You can do this without additional gems.

if params[:id].to_a.size == 40
    ... do stuff
end