What is the difference between procs and lambdas in Ruby?

Now that we've seen procs and lambdas, I think it's important to clarify the difference between the two. There are two key differences in addition to the syntax. Note that the differences are subtle, even to the point that you may never even notice them while programming. Still, they're good to know, especially, if you plan on building advanced programs.

Argument count

The first key difference is that lambdas count the arguments you pass to them, whereas procs do not. Consider this example:

full_name = lambda { |first, last| first + " " + last}  
p full_name.call("Jordan", "Hudgens") 

Running this code will work properly....