Introduction to​​ Python

Background 

Installing Python and JetBrains Pycharm:

www.python.org​​ 

http://www.python.org/download/releases/2.7/​​ 

https://www.jetbrains.com/pycharm/

Code Example 1 - Hello, World!

>>> print "Hello, World!“​​ 

Math in Python

>>> 1 + 1

2​​ 

>>> 6-5

1​​ 

>>> 2*5

10​​ 

>>> 5**2

25​​ 

>>> 21/3

7

>>> 23%3

2​​ 

Python Operators​​ 

Order of Operations:

• parentheses ()​​ 

• exponents **​​ 

• multiplication *, division \, and remainder %​​ 

• addition + and subtraction -​​ 

Comments in Python:

>>> #I am a comment. I can say whatever I want!​​ 

Variables:

print "This program is a demo of variables"

v = 1

print "The value of v is now", v

v = v + 1

print "v now equals itself plus one, making it worth", v

print "to make v five​​ times bigger, you would have to type v = v * 5"

v = v * 5

print "there you go, now v equals", v, "and not", v / 5​​ 

Strings:

word1 = "Good"​​ 

word2 = "Morning"​​ 

word3 = "to you too!"​​ 

print word1, word2​​ 

sentence = word1 + " " + word2 + " " +word3​​ 

print sentence​​ 

Basic Mathematics & Conditional Statements in Python

Boolean operators:

Conditional Statements:

‘if' - Statement​​ 

y = 1

if y == 1:

 ​​ ​​ ​​​​ print "y still equals 1, I was just checking"

‘if - else' - Statement​​ 

a = 1

if a > 5:

 ​​ ​​ ​​​​ print "This shouldn't happen."

else:

 ​​ ​​ ​​​​ print "This should happen."

‘elif' - Statement​​ 

z = 4

if z > 70:

 ​​ ​​ ​​​​ print "Something is very wrong"

elif z < 7:

 ​​ ​​ ​​​​ print "This is normal"

Example

Obtaining data from the user

Tasks:

• Write a program printline.py that prints second prog the sentence “This is my second program”

• Print it as a single​​ line

• Print it with single word on each line

• Which of the following statements are likely to cause problems:​​ 

  • print “This is a valid statement\n”

  • print “This is a valid statement”\n​​ 

  • print “This is a ”valid” statement”​​ 

  • printx “This is a valid statement\n”

• Design a calculator which can perform the Add, Subtract, Multiply and Division operation by using If Else statement?