Question

My code looks like this, and it works:

if Target.find_by_shrunk(params[:shrunk])
  @target = Target.find_by_shrunk(params[:shrunk])
else
  # do something else
end

Target::find_by_shrunk(params[:shrunk]) gets called twice. In order to avoid this, I want to run Target.find_by_shrunk(params[:shrunk]) once, catch the true/false result, then use that variable in the conditional statement. I tried doing this:

does_it_exist = (this_target = Target.find_by_shrunk(params[:shrunk]))
if does_it_exist
  @target = this_target
else
  # do something else
end

But unfortunately that doesn’t do what I want it to.

How do I simultaneously perform an assignment, and somehow capture the true/false result of performing that assignment, so i don’t have to run the same (expensive) piece of code twice in a row?

Answer 1

You could do

unless @target = Target.find_by_shrunk(params[:shrunk])
  # do something else
end

unless is the same as if not. An attribution returns the value attributed, and if it’s different from nil and false, it evaluates to true.