lambda and proc

lambda:

parameter:  block

return: an instance of class Proc

Proc:

procedure

method:  

call:

tell proc to do sth

ex:

test = lambda { |i| i + 1 }

test.call(2)

--> 3

the method to pass parameters

1. test.call(2) 

2.  test[2]

another method to create Proc:

Proc.new {   }