Presgfdjfwwwwwwwwwwqwqeeqentation11.pptx

What is Python?
Python is a popular programming language. It was
created by Guido van Rossum, and released in 1991.
It is used for:
web development (server-side),
software development,
mathematics,
system scripting.

What can Python do?
• Python can be used on a server to create web applications.
• Python can be used alongside software to create workflows.
• Python can connect to database systems. It can also read
and modify files.
• Python can be used to handle big data and perform complex
mathematics.
• Python can be used for rapid prototyping, or for production-
ready software development.

Why Python?
• Python works on different platforms (Windows, Mac, Linux,
Raspberry Pi, etc).
• Python has a simple syntax similar to the English language.
• Python has syntax that allows developers to write programs
with fewer lines than some other programming languages.
• Python runs on an interpreter system, meaning that code
can be executed as soon as it is written. This means that
prototyping can be very quick.
• Python can be treated in a procedural way, an object-
oriented way or a functional way.

example print("Hello, World!")
Variables
• Variables are containers for storing data values.
Creating Variables
• Python has no command for declaring a variable.
• A variable is created the moment you first assign a value to it.
input
x = 5
y = "John"
print(x)
print(y)
Output
5
John

Variables do not need to be declared with any particular type, and can even
change type after they have been set.
Example
x = 4 # x is of type int
x = "Sally" # x is now of type str
print(x)
output
Sally

Casting
• If you want to specify the data type of a variable, this
can be done with casting.
• Example
• x = str(3) # x will be '3'
y = int(3) # y will be 3
z = float(3) # z will be 3.0
Out put will be
3
3
3.0

• Variable Names
• A variable can have a short name (like x and y) or a
more descriptive name (age, carname, total_volume).
Rules for Python variables:A variable name must start
with a letter or the underscore character
• A variable name cannot start with a number
• A variable name can only contain alpha-numeric
characters and underscores (A-z, 0-9, and _ )
• Variable names are case-sensitive (age, Age and AGE
are three different variables)
• A variable name cannot be any of the Python keywords.

• Example
• Legal variable names:
• myvar = "John"
my_var = "John"
_my_var = "John"
myVar = "John"
MYVAR = "John"
myvar2 = "John"
print(myvar)
print(my_var)
print(_my_var)
print(myVar)
print(MYVAR)
print(myvar2)

Many Values to Multiple Variables
• Python allows you to assign values to multiple variables in one line:
• Example
• x, y, z = "Orange", "Banana", "Cherry"
print(x)
print(y)
print(z)
output will be
?
?
?
One Value to Multiple Variables
• you can assign the same value to multiple variables in one line:
• Example
• x = y = z = "Orange"
print(x)
print(y)
print(z)
• Output
• Orange
Orange
Orange

• Unpack a Collection
• If you have a collection of values in a list, tuple etc. Python
allows you to extract the values into variables. This is
called unpacking.
• Example
• Unpack a list:
• fruits = ["apple", "banana", "cherry"]
x, y, z = fruits
print(x)
print(y)
print(z)
Output
apple
banana
cherry

Output Variables
The Python print() function is often used to output variables.
• Example
• x = "Python is awesome"
print(x)
• Variables that are created outside of a function (as in all of the examples in the
previous pages) are known as global variables.
• Global variables can be used by everyone, both inside of functions and outside.
• Example
• Create a variable outside of a function, and use it inside the function
• x = "awesome"
def myfunc():
print("Python is " + x)
myfunc()
Output
Python is awesome

You can display a string literal with the print() function:
• Quotes Inside Quotes
• You can use quotes inside a string, as long as they don't
match the quotes surrounding the string:
• Example
• print("It's alright")
print("He is called 'Johnny'")
print('He is called "Johnny"')

• Control Structures in Python
• Most programs don't operate by carrying out a straightforward
sequence of statements. A code is written to allow making choices
and several pathways through the program to be followed depending
on shifts in variable values.
• All programming languages contain a pre-included set of control
structures that enable these control flows to execute, which makes it
conceivable.
• This tutorial will examine how to add loops and branches, i.e.,
conditions to our Python programs.
• Types of Control Structures
• Control flow refers to the sequence a program will follow during its
execution.

•Selection - This structure is used for making decisions by checking conditions and branching
•Repetition - This structure is used for looping, i.e., repeatedly executing a certain piece of a code block.
Sequential
Sequential statements are a set of statements whose execution process happens in a sequence.
The problem with sequential statements is that if the logic has
broken in any one of the lines, then the complete source code execution will break.
Code
1.# Python program to show how a sequential control structure works
2.
3.# We will initialize some variables
4.# Then operations will be done
5.# And, at last, results will be printed
6.# Execution flow will be the same as the code is written, and there is no hidden flow
7.a = 20
8.b = 10
9.c = a - b
10.d = a + b
11.e = a * b
12.print("The result of the subtraction is: ", c)
13.print("The result of the addition is: ", d)
14.print("The result of the multiplication is: ", e)
Output:
The result of the subtraction is: 10 The result of the addition is : 30 The result of the multiplication is: 200

Selection/Decision Control Statements
• The statements used in selection control structures are also referred to as branching statements or, as their
fundamental role is to make decisions, decision control statements.
• A program can test many conditions using these selection statements, and depending on whether the given
condition is true or not, it can execute different code blocks.
• There can be many forms of decision control structures. Here are some most commonly used control structures:
• Only if
• if-else
• The nested if
• The complete if-elif-else
• Simple if
• If statements in Python are called control flow statements. The selection statements assist us in running a certain
piece of code, but only in certain circumstances. There is only one condition to test in a basic if statement.
• The if statement's fundamental structure is as follows:
• Syntax
1. if <conditional expression> :
2. The code block to be executed if the condition is True
• These statements will always be executed. They are part of the main code.
• All the statements written indented after the if statement will run if the condition giver after the if the keyword is
True. Only the code statement that will always be executed regardless of the if the condition is the statement
written aligned to the main code. Python uses these types of indentations to identify a code block of a particular
control flow statement. The specified control structure will alter the flow of only those indented statements.

1.# Python program to show how a simple if keyword works
2.
3.# Initializing some variables
4.v = 5
5.t = 4
6.print("The initial value of v is", v, "and that of t is ",t)
7.
8.# Creating a selection control structure
9.if v > t :
10. print(v, "is bigger than ", t)
11. v -= 2
12.
13.print("The new value of v is", v, "and the t is ",t)
14.
15.# Creating the second control structure
16.if v < t :
17. print(v , "is smaller than ", t)
18. v += 1
19.
20.print("the new value of v is ", v)
21.
22.# Creating the third control structure
23.if v == t:
24. print("The value of v, ", v, " and t,", t, ", are equal")
Output:
ADVERTISEMENT
The initial value of v is 5 and that of t is 4 5 is bigger than 4 The new value of v is 3 and the t is 4 3 is smaller
than 4 the new value of v is 4 The value of v, 4 and t, 4, are equal

Code
1.# Python program to show how a simple if keyword works
2.
3.# Initializing some variables
4.v = 5
5.t = 4
6.print("The initial value of v is", v, "and that of t is ",t)
7.
8.# Creating a selection control structure
9.if v > t :
10. print(v, "is bigger than ", t)
11. v -= 2
12.
13.print("The new value of v is", v, "and the t is ",t)
14.
15.# Creating the second control structure
16.if v < t :
17. print(v , "is smaller than ", t)
18. v += 1
19.
20.print("the new value of v is ", v)
21.
22.# Creating the third control structure
23.if v == t:
24. print("The value of v, ", v, " and t,", t, ", are equal")
Output:
ADVERTISEMENT
The initial value of v is 5 and that of t is 4 5 is bigger than 4 The new value of v is 3 and the t is 4 3 is smaller than 4 the new value of v is 4 The value of v, 4 and t, 4, are equal

Presgfdjfwwwwwwwwwwqwqeeqentation11.pptx

More Related Content

Similar to Presgfdjfwwwwwwwwwwqwqeeqentation11.pptx (20)

Recently uploaded (20)

Presgfdjfwwwwwwwwwwqwqeeqentation11.pptx