Basics of python 3

Index
1. Types
2. Expressions and Variables
3. String operations
4. Input and output
5. Lists and Tuples
6. Dictionaries
7. Sets
8. Conditions and Branching
9. Loops
10. Functions
11. Objects and Classes

Python Types 11 # integer
561.73 # Float

Python Types 11 # integer
561.73 # Float
“Hello!” # String

Python Types Type function:
type(Expression) Datatype

Python Types Type function:
type(11)  Integer
type(561.73)  Float
type(“Hello!”)  String

Python Types Type Casting:
Type casting is a process of
converting one data type into
another data type.

Python Types Type Casting : Examples
float(11)  11.0
int(561.23)  561
int(“Hello!”)  Error
int(“15”)  15
str(1.25)  “1.25”

Python Types Type Boolean :
True
False

Python Types Type Boolean :
type(True)  bool
type(False)  bool
int(True)  1
bool(1)  True

PYTHON
EXPRESSIONS AND
VARIABLES

Expressions
and
Variables
Expressions :
Expressions describe a type of operations
that computers perform.
Expressions are operations the python
performs, for example, basic arithmetic
operations like adding multiple numbers.

Expressions
and
Variables
Expressions :
Example-1 :
1+2+3+4-5+6+7+8+9+10 = 45
Here,
1 to 10  Operands
+, -  Operators

Expressions
and
Variables
Expressions :
Example-2:
10*6 = 60
Example-3:
20/4 = 5.0  This is regular division
20//4 = 5  This is called integer division

Expressions
and
Variables
Variables :
Variables can be used to store values and
to perform operations.
In python we need not initialize variables
with their datatypes and is automatically
type casted when required.

Expressions
and
Variables
Variables :
Example-1:
A = 5
B = 20
C = A*B-50
Value of C  50

Expressions
and
Variables
Variables :
Example-2:
A = 5+20+25
B = A-15
Value of A  50
Value of B  35

Expressions
and
Variables
Variables :
Example-3:
A = 25
A = A*4
Value of A  100

Strings  In Python, a string is a sequence of characters.
 A string is contained within two quotes. We
can also use single quotes.
 A string can be spaces or digits.
 A string can also be special characters.
 We can bind or assign a string to another
variable.
 It is helpful to think of a string as an ordered
sequence.

Strings Example:
String1 = “Machine Learning”
or
‘Machine Learning’

Strings Example:
String1 = “Machine Learning”
or
‘Machine Learning’
+ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
- -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1
M a c h i n e L e a r n i n g

Strings Example:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Now,
String1[0]  “M”
String1[8]  “L”
String1[-13]  “h”

Strings Example:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
String slicing
String1[0:4]  “Mach”
String1[8:12]  “Lear”
String stride
String1[::2]  “McieLann”
String1[0:9:2]  “McieL”

Strings Example:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
String Length function
len(“String1”)  15
String manipulations
String2 = String1 + “with Python”
String2  “Machine Learning with Python”
String3 = 2*String1
String3  “Machine Learning Machine Learning”

Strings Example:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Strings are immutable
We cannot change the value of a string.
String1[0] = “F”

Strings Example:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Escape sequences:
n  For a new line
t  For a new tab space

Strings Example:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Escape sequences:
Examples:
print(“Machine n Learning”)
Output  Machine
Learning
print(“Machine t Learning”)
Output  Machine Learning

Strings String Methods:
Python has a set of built-in methods that you can use
on strings.
All string methods returns new values.
They do not change the original string.
Let’s suppose two strings ‘A’ and ‘B’
A  Method  B

Example - 1:
A = “Machine Learning with Python”
Let’s try method “upper”
B = A.upper()
print(B)
Output
MACHINE LEARNING WITH PYTHON

Example - 2:
A = “Machine Learning with Python”
Let’s try method “replace”
B =A.replace(‘Python’, ‘R’)
print(B)
Output
MACHINE LEARNING WITH R

Inputs
And
Outputs
Taking inputs
We can use “input()” to take inputs.
But in python 3, default type of the value taken as input is
string.
So if we want to take any other data type inputs, we must
specify it.
And for outputs we can simply use print statement.

Inputs
And
Outputs
Example:
String_input = input()
print(String_input)
Integer_input = int(input())
print(Integer_input)
print(Integer_input + 1)
Float_input = float(input())
print(Float_input)

Python
Lists and
Tuples
Tuples:
In python tuples are an ordered
sequences.
Tuples are immutable.
They are written as comma-separated
values.
Tuples can be nested
Example:
Exampletuple=(1,9,6,8)

Python
Lists and
Tuples
Tuples:
All the three data types in python can be
contained in tuples.
Example
tuple2=(‘ML’, 1, 95.68)
Type of any tuple is the same
type(tuple2)  tuple

Python
Lists and
Tuples
Lists:
In python lists are an ordered sequences
and is represented in square brackets.
Lists are very similar to tuples
Only difference between lists and tuples
is that lists are mutable
Example:
L=[“Machine Learning”, 10 ,5.2]

Python
Lists and
Tuples
Lists:
We can nest lists into lists.
We can also nest tuples into lists
Example:
L=[“Machine Learning”, [10 ,5.2], (“A”,1)]

Python
Dictionaries
Dictionaries:
Dictionaries are a type of collection in
Python.
These are like addresses.
A dictionary has keys and values.
The keys are like addresses but they
don't have to be integers and are usually
characters.

Python
Dictionaries
Dictionaries:
The values are similar to the element in a
list and contain information.
To create a dictionary, we use curly
brackets.
Keys must be immutable and unique.
Each key is followed by a value separated
by a colon.

Python
Dictionaries
Dictionaries:

Python
Dictionaries
Dictionaries:
The values can be immutable, mutable,
and duplicates.
Each key and value pair is separated by a
comma.

Python
Sets
Sets:
Sets are a type of collection of elements.
Unlike lists and tuples, these are
unordered.
These only have unique elements.
Sets are represented using curly
brackets.

Python
Sets
Sets:
Example:
Set1={“A”, “AI”, “ML”, “A”, “B”}
Set1 is stored as
Set1 {“A”, “AI”, “ML”, “B”}

Python
Sets
Sets:
We can also convert a list into a set. This
process is called type casting.
Using:
set_list=set(nameofthelist)

Python
Sets
Sets:
Set operations:
 Add
 Remove
 In – True/False
 Union
 Intersection

PYTHON
Conditions and Branching

Conditions
and Branching
Conditions are branching :
1. If
2. Elif
3. else

Conditions
and Branching
Conditions are branching :

Functions Functions are blocks of code which can
be used on a call.
Python consists of many inbuilt
functions.
Functions can also be defined by the
user

Functions Example:
Range function-

Objects and
Classes
Objects in programming are like objects
in real life.
Like life, there are different classes of
objects.
Instances of a Class: Objects and
Attributes
An instance of an object is the realisation
of a class

Basics of python 3

Recommended

More Related Content

What's hot (20)

Similar to Basics of python 3 (20)

Recently uploaded (20)

Basics of python 3