Lesson 6

Year 9 Python School

Python 3.3

Objectives.

In this lesson students will learn how to output data to the screen and request input from the user.

Students will also learn how to use variables to store data for use in their programs.

Python 3.3

We will be using Python 3.3 to learn the basic of programming and then have look at other languages if there is time.

We will be using the IDLE Interface

Python 3.3

Programming involves using a set of instructions, data and keywords to tell the computer what to do.

Your first program type and then press enter

>>> print(“Hello World”)

Python 3.3

Which one of these is correct?

>>> print"Hello World“

>>> print("Hello World");

>>> Print("Hello World")

>>> print("Hel World")

>>> prin(Hello World)

Where do you look for errors?

1) Syntax Errors2) Logical errors

Python 3.3

Task

Using a script – create a program that produces three lines of text.

Python 3.3

Special characters in text

\n Creates a line in a string of text

\t Creates a tab style indent in a string of text

\\ Allows a backslash to appear in a string of text

\” Allows a speech mark to be used in a string of text

Python 3.3

Variables

Variables are containers that can hold data.

In most languages variables are declared to be a certain data type first such as

Strings, Integers, Dates, Real, Characters etc..

In python variables are declared when they have their first value assigned to them

Python 3.3

Variables

Try the following program

print("Hello this is a variable program")name = ""name = input("Enter in your name please: ")print("Hello ", name)

Python 3.3

Variables

You can use variables to do calculations

Try this program

print("Hello this is a variable program")num1 = 0num2 = 0sum = 0num1 = int(input("Enter in number 1 please: "))num2 = int(input("Enter in number 2 please: "))sum = num1 + num2print("The total is ",sum)

Python 3.3

Tasks

Watch the three python videos under lesson 01 and then answer the questions on the worksheet.

Python 3.3

String Functions.

Len(variable) = returns length

Variable.upper() – returns uppercase of string

Variable.lower() – returns lowercase of string.

Variable.capitalise() – Makes the first letter of the string capital.

Variable.replace(“old word”,”new word”) – Replaces a word in a string with the new word.

Python 3.3

String Functions.

astring = "Hello World"print(astring[:2])print(astring[6:])print(astring[:5])

Output –

HeWorldHello

Can you workout what the code is doing from the output?