03 - Creating Functions

Note: Watch the following video from www.teachyourselfpython.com for an overview of functions and parameter passing

  Subroutines may also be referred to as a function, procedure, or subprogram

  It is a portion of code that may be called and executed anywhere in a program and used repeatedly

  All of the above are valid definitions / examples of subroutines

  They are made up of a sequence of instructions that can receive data, process that data, and return a value.

  returns a single value (a procedure performs operations but does not necessarily return a value)

  always returns the number 1

  returns a function

  returns several values

  import command (e.g. import main():)

  None of the above

  def command (e.g. def main():)

  system command

def mainmenu():
  print("===Welcome to the Main Menu====")
  

def partone():
  print("===This is part one=====")

mainmenu()

  Replace line 8 with print("def part one()"

  Replace line 8 with "part1"

  Replace line 8 with partone()

  This cannot be done as the main menu must be called first

def one():
  print(1)


def two():
  print(2)

one()

  1,2

  print(one)

  1

  one,two

def one():
  print(1)
  two()


def two():
  print(2)
  three()

one()

  The program will only print 1

  None of the above

  The program will crash because the function 'three' is being called and does not exist

  The program will print 1,2,3

import time

def bank():
  print("Welcome to your bank!")
  print("Verifying account number:>>")
  time.sleep(1.4)
  print(".................")
  print("Verifying password:>>")
  time.sleep(1.4)
  print(".....Logging you in to your account")
  time.sleep(1.4)
  print("===Please Wait===")
  time.sleep(1.4)
  print(".................")
  account()

def account():
  print("========WELCOME TO YOUR ACCOUNT======")
  password=input("Enter secure password:")
  denied()


bank()

  One function - time.

  Two functions - bank and account

  Three functions - def, time and sleep

  Five functions, bank, time, sleep, accout and def

def main()
  print("This is the main function"

def function1():
print("This is function1")
  

def function2:
  print("This is function2")
  
main()

  A colon after main() at the very bottom of the program

  A double brackets after main()

  A colon after def main()

  None of the above

import time

def main():
  print("---LATEST PHONES.COM----")
  time.sleep(1.3)
  print("printing list of top phones...please wait.....")
  topthree()
  
def topthree():
  print("Top Three phones are:Samsung, Nokia and HTC")
  #add the top three, in your opinion, here
  time.sleep(1.3)
  print("...now we are going to list the worst phone ever...please wait")
  worst()

main()

  It will not run and cause an error, as there are no functions defined

  It will print the top three phones and the statement leading up to printing the worst phones and then stop as there is no 'worst' function

  None of the above

  It will print the top three phones and the three worst phones before exiting the program

def main():
  x=2
  y=3
  sum(x,y)

def sum(x,y):
  print(x+y)


main()

  x

  x and y

  def and print

  main and sum

def main():
  num1=7
  num2=2
  sum(x,y)

def sum(x,y):
  print(x+y)
  
main()

  It will fail to run. You are calling the function 'sum' with parameters x and y, but they don't exist

  The program will execute and print the letters x + y

  The proram will print '9' twice.

  The program will execute and print the number 9 (adding parameters x + y)

  reusability

  fast execution

  prevention of misuse

  automated validation

def main():
  username="user1"
  welcome(username)

def welcome(username):
  print(username)
  
main()

  There are no parameters here -parameters can only be numbers. The code will fail

  An error will occur as the parameter 'username' has been used, and this is not valid

  The parameter is 'username' and 'user1' will be printed to the screen

  The parameter is 'user1' and 'username' will be printed to the screen

def one():
  x=1
  print(x)
  two()


def two():
  x=2
  print(x)
  three()

def three():
  x=3
  print(x)
  add(x)
  
def add(x):
  print(x)
  
one()

  1,2,3,6

  1,2,3,3

  Error - the code will fail to run as the same parameter x has been used repatedly

  1,2,3

value_of_goods=10

def vat(value_of_goods):
  return value_of_goods * 0.2

print(vat(value_of_goods))

  An error occurs as you cannot print out the result of a function as has been done on line 6

  None of the above

  The function vat is called with the parameter '10' and 10 is printed at program line 6

  The function vat multiples the parameter 'value_of_goods' by 0.2 and returns 2.0 (the value of the function is printed)