An introduction to Python

A series of introductory lessons to Python that does not use too much

maths!

Write a poem

Let us write a four line poem

Challenge 1

print("Mashed potatoes on the ceiling.")print("Green beans on the floor.")print("Stewed tomatoes in the corner.")print("Squash upon the door.")

Change a vegetable

We are now going to change the program so that we can alter the name of one of the vegetables

To do this we need to:• Add a variable• Make sure that it appears in a line

Challenge 2

veg="Carrots“print("Mashed "+veg+" on the ceiling.")print("Green beans on the floor.")print("Stewed tomatoes in the corner.")print("Squash upon the door.")

Challenge 3

Can you change the program so that the variable appears in every line?

# for exampleprint("Green“+veg+"on the floor.")print(veg+"on the door.")

Challenge 3

veg="Carrots"print("Mashed "+veg+" on the ceiling.")print("Green "+veg+" on the floor.")print("Stewed "+veg+" in the corner.")print(veg+" upon the door.")

Make the computer input

We are now going to change the program so that the computer accepts an input from the keyboard

Challenge 4

veg=input("Type in the name of a vegetable ")print("Mashed "+veg+" on the ceiling.")print("Green "+veg+" on the floor.")print("Stewed "+veg+" in the corner.")print(veg+" upon the door.")

Have four different vegetable

Instead of having just one input can you change the program so that it has four – one for each line.

Challenge 5Change hereChange hereChange hereChange hereprint("Mashed“+ Change here+ " on the ceiling.")print("Green“+ Change here+" on the floor.")print("Stewed“+ Change here+" in the corner.")print(Change here+" upon the door.")

# for exampleveg1=input ("What is vegetable 1? ")

veg2=input("What is vegetable 2? ")………….

# for example

print("Mashed "+veg1+" on the floor")

print("Green "+veg2+"on the floor.")

Challenge 5

veg1=input("What is vegetable 1? ")veg2=input("What is vegetable 2? ")veg3=input("What is vegetable 3? ")veg4=input("What is vegetable 4? ")print("Mashed"+veg1+ "on the ceiling.")print("Green"+veg2+" on the floor.")print("Stewed"+veg3+" in the corner.")print(veg4+" upon the door.")

Random vegetable

Now lets change the program so that random vegetables are displayed

To do this we need to:• Import the commands for the random library• Create a list with vegetable names• Choose a vegetable

First part of the program

# To use random numbersimport randomveglist=[“Beans", “Brocolli", “Cabbage", “Cauliflower"]veg=random.choice(veglist)

Challenge 6#to use random numbersimport randomveglist=["Beans","Broccoli","Cabbage"]veg=random.choice(veglist)print("Mashed "+veg+ "on the ceiling.")print("Green "+veg+" on the floor.")print("Stewed "+veg+" in the corner.")print(veg+" upon the door.")

Challenge 7Create a program that randomly chooses a member of your class

• Create a new list with names of you class• Randomly choose a name• Print the chosen name

Challenge 8Create a program to roll a six sided dice

Challenge 9

Unfortunately our program does not look too good at the moment.

We can make it look a lot better by using a library of commands called easygui

The gui stands for Graphical User Interface

GUI Poem#load the easygui commands

from easygui import *

title="Poem“

veg=enterbox("Type the name of a vegetable ")

message=("Our poem is about a "+veg)

msgbox(message, title)

message=("Mashed "+veg+" on the ceiling")

msgbox(message, title)

Enter the program as shown on the right.

What do you think will happen?

Run it and see

Challenge 10

Can you add the other lines of the poem?

Challenge 11

Like to guess what these lines do?

msg ="Choose a vegetable?"choices = ["Pea", "Parsnip", "Aubergine", "Tomato"]veg = buttonbox(msg, title, choices)

Challenge 11

Add the lines to your program and see if they work

Challenge 12What does changing buttonbox for choice box

have?

Challenge 13

Let’s create a quiz program

Challenge 13correct = 0print("Here is a quiz to test your knowledge of television") print() print("Question 1") print("What type of animal is Shaun?") print() print("a. Cow") print("b. Dog") print("c. Sheep") correct = "c"answer = input("Make your choice: ") if answer == correct: print("Right Answer!")else: print("Wrong Answer! “)

Challenge 13correct = 0print("Here is a quiz to test your knowledge of television") print() print("Question 1") print("What type of animal is Shaun?") print() print("a. Cow") print("b. Dog") print("c. Sheep") correct = "c"answer = input("Make your choice: ") if answer == correct: print("Right Answer")else: print("Wrong Answer! ")

Try to think of a reason for the two equal signs

It is called a logic test

Challenge 14

Can you add two more questions?

Challenge 15

We would like to add a score to the quiz

To do this we need to:• create a variable – score• If correct we will add one to the score• We will also print the score

Challenge 15

Add score = 0 as the first line of the program

Within the if commands (you have to do this for all 3 questions

if answer == correct: print("Right Answer") score=score+1else: print("Wrong Answer! ")print("The score is "+str(score)+" out of 3")

Challenge 15correct=0score = 0print("Here is a quiz to test your knowledge of television")print()print("Question 1")print("What type of animal is Shaun")print()print("a. Cow")print("b. Dog")print("c. Sheep")correct = "c"answer = input("Make your choice: ")if answer == correct: print("Right Answer!") score = score+1else: print("Wrong Answer!")print("The score is "+str(score)+" out of 3")

Challenge 16

Can you use the easygui commands (challenge 9-12) to make the quiz easier to use?

Challenge 17

We are now going to make another type of quiz

One which tests multiplication tables

Run the code on the next slide and check that the program works

Can you explain what each line does?

Challenge 17#import random libraryimport random

number1=random.randint(1,12)number2=random.randint(1,12)

print("What is "+str(number1)+ " x "+str(number2)+" ?");answer=input()#change the answer into a numberanswer=int(answer)

if answer == (number1*number2): print("Correct")else: print("Wrong")

Challenge 18This only does one question

We would like more than that so we will use a loop

The loop surrounds the program like this:

question = 1while question<6: program question=question+1

Everything that you want to happen in the loop must be indented (moved in) 3 spaces

Challenge 18#import random libraryimport randomquestion= 1while question<6: number1=random.randint(1,12) number2=random.randint(1,12)

print("What is "+str(number1)+" x "+str(number2)+ “ ?"); answer=input() #change the answer into a number answer=int(answer)

if answer == (number1*number2): print("Correct") else: print("Wrong") question=question+1

Challenge 19

Can you change the program to ask 10 questions?

Challenge 20

Can you change the program so that is keeps a score and is easier to use (use easygui)?