Python: Objects

Talk = ''

def create_greeting(greeting=None):
    global Talk
    Talk = greeting + ' fellow blogsters! '
    return Talk

create_greeting('Hello')
Talk += 'How are we doing today?'

def create_sign(greeting, decoration = "*"):
    line = decoration * len(greeting) # len(STRING) gets the length of a string
    print(line)
    print(greeting)
    print(line)

create_sign(Talk)

Objects

• You can make functions by

  • def FUNCTIONAME(PARAM)

• Named references should be thought of as objects rather than variables
  • Assignment attaches a name to the object
  • Changing assignment from one reference to another puts two different names referring to the same object
  • The is operator determines if references are the same object

    • List1 = [1,2,3]
      List2 = List1
      print(List1 is List2) # prints True

• Python garbage collector reclaims unreachable objects
• Function arguments can be specified with defaults
• The default expressions are evaluated once when def is executed for the first time
• Global references can be read from a local scope but only when you specify

  • global VARIABLE_NAME