Python 2

Variables, Assignment and Types

Personality Testeryournumber = input("Please enter a number between 1 and 99: ")print "You entered " , yournumberprint "Performing personality analysis on your number choice …"if yournumber < 49: print "You are truly inadequate"else: print "You have delusions of grandeur"print "That's all folks"

Values• A basic thing – a letter or a number

• Values have TYPES

• Integers 1, 29485• Strings “Hello world”• Float – floating point 3.14159

Variables• A variable has a value

mynumber

Variable names• Can’t begin with a number• Can’t contain spaces or other funnies• Can’t be a keyword

– Type help() and press return– Then type keywords in the box.

AssignmentPutting a Value ‘into’ a Variable• myVariable = 23• myLongVariable = “Hello how’s it going”Sometimes written with an arrow• myVariable 23

Assignment is really a sort of COPYWhy?

Assignment quiz• What’s the value of myVariable

myVariable = 22mySecondVariable = 13myVariable = mySecondVariablemyVariable = str(myVariable)

Statements• A statement is a piece of code that

Python can execute.• Lots of statements make a script• Scripts are the same as programs

Operators• Operators ‘do things’ to operands• The simplest operators are the math

+ addition 5+2- subtraction 5-2* multiplication 5*2/ division 5/2** exponentiation 5**2% modulo 5%2

Now we can do the first part of the Python Challenge!

A useful program• Write a Fahrenheit to Celsius converter • The formula for the conversion is: F = 1.8 * C + 32 • To make this program work you will need to do the

following: Get the user input using input(“your prompt here”) Assign the result to a variable.

• That will give you a number, but it will be in a string type. You’ll need to convert it to an integer type using int(variablename).

• Now you have an integer, multiply it by 1.8 and add 32

• Print the result – your answer, to the screen with print variablename

Challenge• Write a script/program that allows you to

input two numbers and calculates their:– Product– Sum– Difference– Quotient (one number divided by the other

without any remainder)– Remainder (remainder when one is divided by

the other)– Exponent (one number to the power of the other)

Challenge 2• Create an object

• Find its type– Print (type(myobject))

• Find its id– Print (id(myobject))

• What is that?