MODULE 5
Integrative Programming & Technology
PYTHON BASIC
BSIT 3A
Prepared by:
REYNEL M. MARGELINO
Faculty
Python Basic
Lesson Objectives:
At the end of this lesson, you will be able to:
•
•
•
•
•
•
•
Install python software.
Understand the benefits of learning python
Learn Python Basic Syntax
Learn Python Variable Types
Learn Python Operators
Learn Python Input () & Selection Function
Learn Python iteration (looping)
PYTHON OVERVIEW
WHAT IS PYTHON?
•
Is a general-purpose interpreted, interactive, object-oriented, and highlevel programming language.
•
It was created by Guido van Rossum during 1985- 1990.
•
Source code is also available under the General Public License (GPL).
WHY TO LEARN PYTHON?
•
A high-level, interpreted, interactive and object-oriented scripting
language.
•
Python is designed to be highly readable. It uses English keywords
frequently where as other languages use punctuation, and it has fewer
syntactical constructions than other languages
KEY ADVANTAGES OF LEARNING PYTHON
•
Python is Interpreted − Python is processed at runtime by the interpreter.
You do not need to compile your program before executing it. This is similar
to PERL and PHP.
•
Python is Interactive – You can actually sit at a Python prompt and interact
with the interpreter directly to write your programs.
•
Python is Object-Oriented − Python supports Object-Oriented style or
technique of programming that encapsulates code within objects.
•
Python is a Beginner's Language − Python is a great language for the
beginner-level programmers and supports the development of a wide
range of applications from simple text processing to WWW browsers to
games.
PYTHON APPLICATION
1.
2.
3.
4.
5.
6.
GUI based desktop applications (Games, Scientific Applications)
Web frameworks and applications
Enterprise and Business applications
Operating Systems
Language Development
Prototyping
ORGANIZATIONS USING PYTHON
1.
2.
3.
4.
5.
6.
7.
8.
9.
Google (Components of Google spider and Search Engine)
Yahoo(Maps)
YouTube
Mozilla
Dropbox
Microsoft
Cisco
Spotify
Quora
PYTHON-ENVIRONMENT SETUP
Python is available on a wide variety of platforms including Linux and Mac OS X.
Let's understand how to set up our Python environment.
INSTALLING PYTHON
Python distribution is available for a wide variety of platforms. You need to
download only the binary code applicable for your platform and install Python.
The most up-to-date and current source code, binaries, documentation, news,
etc., is available on the official website of Python https://www.python.org/
You can download Python documentation from https://www.python.org/doc/.
The documentation is available in HTML, PDF, and PostScript formats.
UNIX AND LINUX INSTALLATION
Here are the simple steps to install Python on Unix/Linux machine.
•
Open a Web browser and go to https://www.python.org/downloads/.
•
Follow the link to download zipped source code available for Unix/Linux.
•
Download and extract files.
•
Editing the Modules/Setup file if you want to customize some options.
•
run ./configure script
•
make
•
make install
This installs Python at standard location /usr/local/bin and
at /usr/local/lib/pythonXX where XX is the version of Python.
its libraries
WINDOWS INSTALLATION
Here are the steps to install Python on Windows machine.
•
Open a Web browser and go to https://www.python.org/downloads/.
•
Follow the link for the Windows installer python-XYZ.msi file where XYZ is the
version you need to install.
•
To use this installer python-XYZ.msi, the Windows system must support
Microsoft Installer 2.0. Save the installer file to your local machine and then
run it to find out if your machine supports MSI.
•
Run the downloaded file. This brings up the Python install wizard, which is
really easy to use. Just accept the default settings, wait until the install is
finished, and you are done.
MACINTOSH INSTALLATION
Recent Macs come with Python installed, but it may be several years out of date.
See http://www.python.org/download/mac/ for instructions on getting the
current version along with extra tools to support development on the Mac. For
older Mac OS's before Mac OS X 10.3 (released in 2003), MacPython is available.
Jack Jansen maintains it and you can have full access to the entire
documentation at his website − http://www.cwi.nl/~jack/macpython.html. You
can find complete installation details for Mac OS installation.
PYTHON-BASIC SYNTAX
Variables and Data Structures
•
In other programming languages like C, C++ and Java, you will need to
declare the type of variables but in Python you don’t need to do that. Just
type in the variable and when values will be given to it, then it will
automatically know whether the value given would be a int, float or char
or even a String.
PYTHON-VARIABLE TYPES
•
•
•
Variables are nothing but reserved memory locations to store values. This
means that when you create a variable you reserve some space in
memory.
Python variables do not need explicit declaration to reserve memory
space. The declaration happens automatically when you assign a value
to a variable. The equal sign (=) is used to assign values to variables.
Python variables do not need explicit declaration to reserve memory
space. The declaration happens automatically when you assign a value
to a variable. The equal sign (=) is used to assign values to variables.
ASSIGNING VALUES TO VARIABLES
•
Example
counter = 100
# An integer assignment
miles = 1000.0
# A floating point
name
= "John"
# A string
MULTIPLE ASSIGNMENT
•
Python allows you to assign a single value to several variables
simultaneously
Example:
A=B=C=1
STANDARD DATA TYPES
1. Numbers
2. String
3. List
4. Tuple
5. Dictionary
NUMBERS
PYTHON PROGRAM TO DECLARE VARIABLES
a. myNumber = 3
print(myNumber)
b. myNumber2 = 4.5
print(myNumber2)
c. myNumber ="helloworld"
print(myNumber)
PYTHON OPERATORS
Operators are used to perform operations on variables and values.
Python divides the operators in the following groups:
•
•
•
•
•
•
•
Arithmetic operators
Assignment operators
Comparison operators
Logical operators
Identity operators
Membership operators
Bitwise operators
PYTHON ARITHMETIC OPERATORS
Arithmetic operators are used with numeric values to perform common
mathematical operations:
PYTHON ASSIGNMENT OPERATORS
Assignment operators are used to assign values to variables:
PYTHON COMPARISON OPERATORS
Comparison operators are used to compare two values:
PYTHON LOGICAL OPERATORS
Logical operators are used to combine conditional statements:
PYTHON IDENTITY OPERATORS
Identity operators are used to compare the objects, not if they are equal, but if
they are actually the same object, with the same memory location:
PYTHON MEMBERSHIP OPERATORS
Membership operators are used to test if a sequence is presented in an object:
PYTHON BITWISE OPERATORS
Bitwise operators are used to compare (binary) numbers:
PYTHON INPUT () FUNCTION
The input() function allows user input.
Example
x = input('Enter your name:')
print('Hello, ' + x)
OUTPUT
Create a program using python to get the product of two numbers
1. Open your Python IDLE
2. Click File new file and save it as product .py
3. Copy the code below
num1 = int(input("Enter num1: "))
num2 = int(input("Enter num2: "))
num3 = num1 * num2
print("Product is: ", num3)
4. To run press f5
OUTPUT
PYTHON SELECTION FUNCTION
Selection in Python is made using the two keywords ‘if’ and ‘elif’ and else (elseif)
With the same instruction copy the code below and run by pressing f5
CODE
OUTPUT
num1 = 34
if(num1<12):
print("Num1 is good")
elif(num1<35):
print("Num2 is better")
else:
print("Num2 is great")
PYTHON ITERATION (LOOPING)
THE WHILE LOOP
•
With the while loop we can execute a set of statements as long as a
condition is true.
Example
Print i as long as i is less than 6:
i=1
while i < 6:
print(i)
i += 1
OUTPUT
WHILE LOOP: THE BREAK STATEMENT
•
With the break statement we can stop the loop even if the while
condition is true:
Example
Exit the loop when i is 3:
i=1
while i < 6:
print(i)
if i == 3:
break
i += 1
OUTPUT
WHILE LOOP: THE CONTINUE STATEMENT
With the continue statement we can stop the current iteration, and continue
with the next:
Example
Continue to the next iteration if i is 3:
i=0
while i < 6:
i += 1
if i == 3:
continue
print(i)
# Note that number 3 is missing in the result
OUTPUT
WHILE LOOP: THE ELSE STATEMENT
With the else statement we can run a block of code once when the condition
no longer is true:
Example
Print a message once the condition is false
i=1
while i < 6:
print(i)
i += 1
else:
print("i is no longer less than 6")
OUTPUT
PYTHON FOR LOOPS
A for loop is used for iterating over a sequence (that is either a list, a tuple, a
dictionary, a set, or a string).
This is less like the for keyword in other programming languages, and works more
like an iterator method as found in other object-orientated programming
languages.
With the for loop we can execute a set of statements, once for each item in a
list, tuple, set etc.
Example
Print each fruit in a fruit list:
fruits = ["apple", "banana", "cherry"]
for x in fruits:
print(x)
OUTPUT
The for loop does not require an indexing variable to set beforehand.
LOOPING THROUGH A STRING
Even strings are iterable objects, they contain a sequence of characters:
Example
Loop through the letters in the word "banana":
for x in "banana":
print(x)
OUTPUT
PYTHON FOR LOOPS: THE BREAK STATEMENT
With the break statement we can stop the loop before it has looped through all
the items:
Example
Exit the loop when x is "banana":
fruits = ["apple", "banana", "cherry"]
for x in fruits:
print(x)
if x == "banana":
break
OUTPUT
PYTHON FOR LOOPS: THE CONTINUE STATEMENT
With the continue statement we can stop the current iteration of the loop, and
continue with the next:
Example
Do not print banana:
fruits = ["apple", "banana", "cherry"]
for x in fruits:
if x == "banana":
continue
print(x)
OUTPUT
PYTHON FOR LOOPS: THE RANGE() FUNCTION
To loop through a set of code a specified number of times, we can use
the range() function,
The range() function returns a sequence of numbers, starting from 0 by default,
and increments by 1 (by default), and ends at a specified number.
Example
Using the range() function:
for x in range(6):
print(x)
OUTPUT
Note that range(6) is not the values of 0 to 6, but the values 0 to 5.
The range() function defaults to 0 as a starting value, however it is possible to
specify the starting value by adding a parameter: range(2, 6), which means values
from 2 to 6 (but not including 6):
Example
Using the start parameter:
for x in range(2, 6):
print(x)
OUTPUT
The range() function defaults to increment the sequence by 1, however it is
possible to specify the increment value by adding a third parameter: range(2,
30, 3):
Example
Increment the sequence with 3 (default is 1):
for x in range(2, 30, 3):
print(x)
OUTPUT
PYTHON FOR LOOPS: ELSE IN FOR LOOP
The else keyword in a for loop specifies a block of code to be executed when
the loop is finished:
Example
Print all numbers from 0 to 5, and print a message when the loop has ended:
for x in range(6):
print(x)
else:
print("Finally finished!")
OUTPUT
NESTED LOOPS
A nested loop is a loop inside a loop.
The "inner loop" will be executed one time for each iteration of the "outer loop":
Example
Print each adjective for every fruit:
adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "cherry"]
for x in adj:
for y in fruits:
print(x, y)
OUTPUT
THE PASS STATEMENT
for loops cannot be empty, but if you for some reason have a for loop with no
content, put in the pass statement to avoid getting an error.
Example
for x in [0, 1, 2]:
pass
OUTPUT
# having an empty for loop like this, would raise an error without the pass
statement
SUMMARY
•
•
•
•
•
•
•
•
Python is a general-purpose interpreted, interactive, object-oriented, and
high-level programming language.
Python is designed to be highly readable.
In python the variables and data structures
in other programming languages like c, c++ and java need to declare the
type of variables but in python you don’t need to do that.
Python allows you to assign a single value to several variables
simultaneously
Python operators are used to perform operations on variables and values
Python input() function allows user input.
Python selection is made using the two keywords ‘if’ and ‘elif’ and else
(elseif)
Python Iteration (Looping) can execute a set of statements as long as a
condition is true.
Enrichment Activity
I.
Quiz (TRUE OR FALSE)
Instructions:
✓ Write the letter A if your answer is True and B if False on the separate.
1. Python is a general-purpose compiled, interactive, object-oriented, and
high-level programming language.
2. Python is a high-level, interpreted, interactive and object-oriented
scripting language.
3. Python is not designed to be highly readable.
4. YouTube is considered as one of the company that uses python
language.
5. Python didn’t supports Object-Oriented style.
6. Python variables need to explicit declaration to reserve memory space.
7. Python allows you to assign a single value to several variables
simultaneously.
8. Python Operators are used to perform operations on variables and values.
9. Python assignment operators are used to assign values to variables
10. output()function allows user input.
MULTIPLE CHOICE
Instructions:
✓ Write the letter of the correct answer on the separate sheet.
✓ Choose the best answer
11.
A.
B.
C.
D.
we can stop the loop even if the while condition is true:
Break Statement
Continue Statement
Else Statement
None of these
12.
A.
B.
C.
D.
13.
A.
B.
C.
D.
we can run a block of code once when the condition no
longer is true
Break Statement
Continue Statement
Else Statement
None of these
statement we can stop the current iteration, and
continue with the next
Break Statement
Continue Statement
Else Statement
None of these
14. The range() function is usually used in
A. FOR LOOPS
B. WHILE LOOPS
C. DO WHILE
D. None of these
15.
A. FOR LOOPS
B. WHILE LOOPS
C. DO WHILE
D. None of these
is a loop inside a loop.
16. What would be the output of the following code?
for x in range(3):
print(x)
else:
print("Finally finished!")
A.
B.
C.
D.
E. None of These
17. What would be the possible code for the output below?
A. myNumber ="Hello World"
print(myNumber)
B. myNumber ="Hello World"
print ”myNumber”
C. myNumber ="Hello Wold"
print(myNumber)
D. myNumber ="Helo World"
print(myNumber)
E. None of These
18. In Python Operators “=” belongs to
A.
B.
C.
D.
E.
Logical operators
Identity operators
Membership operators
Bitwise operators
None of These
19. In Python Operators “and” belongs to
A.
B.
C.
D.
E.
group
Logical operators
Identity operators
Membership operators
Bitwise operators
None of These
20. In Python Operators “in” belongs to
A.
B.
C.
D.
E.
group
Logical operators
Identity operators
Membership operators
Bitwise operators
None of These
group