7. Input Output

Learning outcomes

You will learn to use:

The input function

The int function

String formatting

Number formatting

Activity 6.1

Input function

The input function allows the user to input a value and assign it to a variable.

•

Copy and run this program.

myAnswer=input("Please enter your name: ")

print(myAnswer)

•

Re-run the program several times, entering different names each time.

•

Write a program that asks the user for their name and favourite food and displays these on the screen.

Activity 6.2

Int function

•

Copy and run this program.

age=input("Please enter your age: ")

agePlusTen = age + 10

print("You will be",agePlusTen,"in 10 years")

•

Explain why it does not work.

•

Correct the program.

Activity 6.3

Write a program that asks you to enter a number then displays the number doubled.

Activity 6.4

String formatting

The string method .format gives you more control over the formatting of your output than printing using space-separated values. The string formatting commands are given in curly brackets {}.

•

Copy and run these lines of code:

>>>foodOne="fish"

>>>foodTwo="chips"

>>>print("{0} and {1}".format(foodOne,foodTwo))

fish and chips

>>>print("{1} and {0}".format(foodOne,foodTwo))

chips and fish

>>>print("{1} {1} {1}  and {0} {0} {0}".format(foodOne,foodTwo))

chipschipschips and fishfishfish

•

Create these variables:

one = “cheese”

two =”onion”

•

Use the .formatcommand to display:

My favourite crisps are cheese and onion. I love them!

cheese and onion and cheese and onion and cheese and onion

cheesecheesecheese and oniononiononion

You guessed it. The best crisps are onion and … cheese.

•

Try altering the flavours assigned to the variables to your favourite flavour! Enjoy.

Activity 6.5

Formatting numbers

You can use the .format method to format the number of decimal places.  

•

Copy and run these lines of code:

>>>number = 98.1468297645

>>>print("The answer is {0:.5f}".format(number))

The answer is 98.14683

>>>print("The answer is {0:.4f}".format(number))

The answer is 98.1468

>>>print("The answer is {0:.3f}".format(number))

The answer is 98.147

>>>print("The answer is {0:.1f}".format(number))

The answer is 98.1

>>>print("The answer is {0:.0f}".format(number))

The answer is 98

•

Assign the number 765.87641987 to a variable and display the number with 5, 2 and no decimal places using the .format command.

Activity 6.6

•

Write a program that asks how much your bill is at a restaurant and then asks you to enter the % you want to give in a tip. The program should display the amount of tip to give to the waiter.

•

Amend the program so that it also displays the total cost of the meal including the tip.

Activity 6.7

•

Write a program that displays the square of a number.

•

Write a program that prompts for a number and then displays the cube of a number.

•

Write a program to find the perimeter of a square.

•

Write a program to find the perimeter of a rectangle.

•

Write a program that finds the area of a square.

•

Write a program that finds the area of a cube.

•

Write a program to convert from pounds to euros.

Hint: All these programs should prompt for the input information and display the result appropriately.