As you know with the growth in Machine Learning & Artificial Intelligence, the future of the industry will be dependent on AI-based applications. Python is the stepping stone to start your career in automation and data science.
Few real-time application of Python:
- Web Scraping
- Image Processing
- Machine Learning & AI
- Automate excel & CSV files
- Scientific & Numeric Computing
- Email Automation
- Data Analysis
- Data Visualization
- Web Development using Django
- Gaming development
Benefits of using Python over other programming languages:
- Open Source (No license required to buy software) & supports Community development
- Extensively Support multiple Libraries
- Data Analysis is done using Pandas
- Numerical Calculation is done using NumPy
- Object-Oriented programming language
- Python is easier than C, C++, Java, .Net, etc.
- High-performance speed
- Better productivity
- User-friendly data-structures
All top companies like Google, Facebook, Microsoft, Youtube, Quora, Yahoo, Salesforce are currently using Python.
This tutorial will cover:-
- Python Installation
- Python Data Types
- Numbers
- Strings
- List
- Tuple
- Dictionary
- Sets
- Operators
- Conditionals Statements
- Loops
- Functions
- File Handling
How to install Python
- Download python latest version from anaconda.com/download/
- Complete setup installation
- Install visual studio code from code.visualstudio.com
- Start using Jupyter notebook
Variables
Python stores data/ values in memory using a variable. A variable is a name given by you, to which you assign a piece of data that is stored in an area of the computer’s memory, allowing you to refer to that data when you need to later in the program
a = 10
b = ‘Welcome to Gyansetu!’
c = 10.11
print(a,b,c)
## output:
## 10 Welcome to Gyansetu! 10.11
Here the variables are a, b, c
Python Data Types
Numbers:
There are 3 types of Numbers:
- Integer
- Float
- Complex
- Integer (int): Integer is a non-decimal number formed by the combination of 0 – 9 digits.
- Float (float): A float is a decimal number that can be represented on a number line.
- Complex (complex): They are the numbers consist of an imaginary number and a real number.
Different types of numbers
a = 10 #integer
c = 1 + 2j #complex
To accept values from user input
x = input("Enter any number : ")
y = input("Enter any number : ")
z = input("Enter any number : ")
print(x,y,z)
## output: ## Enter any number : 2 ## Enter any number : 3 ## Enter any number : 1 ## 2 3 1
To know the type of data:
print(type(x))
print(type(y))
print(type(z))
## output: ## ## ##
String
A string in Python consists of a series or sequence of characters – letters, numbers, and special characters.
Strings can be indexed – often synonymously called subscripted as well. Similar to C, the first character of a string has the index 0.
How to print a string
a = "sahil" b = 20 c = 30 print("%d-%d-%d" % (a,b,c)) ## output: ## This will give error because %d is used in print for a and a is a string, %d is used for integer values
### Another way to solve the error
a = "sahil" b = 20 c = 30 print("%s-%d-%d" % (a,b,c)) ## output: ## sahil-20-30 ## %s is used for string values
How to print a string using .format
a = "sahil" b = 20 c = 30 print("{}-{}-{}".format(a,b,c)) ## output: ## sahil-20-30
Indexing in Python:
Indexing # starts from 0 to n – 1 where n is the length of string use []
Example to understand indexing:
s = "Hello World!" print(s[2]) print(s[6]) ## output: ## l ## s
Slicing in Python:
Slicing # used to make sub-strings from strings used with start, end, and step variable
# s[start:end:step] s = "Hello World!" x = s[3:11] y = s[:] z = s[:6] p = s[6:] print(x) print(y) print(z) print(p) print(s) ## output: ## lo World ## Hello World! ## Hello ## World! ## Hello World!
Basic String Functions: –
Swapcase:- used to change uppercase letters into lowercase letters and vice versa
Upper:- It changes all letters into uppercase and returns the string
Lower:- It changes all letters into lowercase and return the string
Strip:- strip is used to remove all leading and trailing spaces from the string
Lstrip:- It is used to remove left space
Rstrip:- It is used to remove the right space
Example to understand string functions:
s = input("Enter a String : ") print(s) print("Swapcase : ",s.swapcase()) print("Upper : ",s.upper()) print("Lower : ",s.lower()) print("Strip : ",s.strip()) print("LStrip : ",s.lstrip()) print("RStrip : ",s.rstrip()) ## output: ## Enter a String : iclass gyansetu ## iclass gyansetu ## Swapcase : ICLASS GYANSETU ## Upper : ICLASS GYANSETU ## Lower : iclass gyansetu ## Strip : iclass gyansetu ## LStrip : iclass gyansetu ## RStrip : iclass gyansetu
Lists
- Lists are one of the most powerful tools in Python.
- They are just like the arrays declared in other languages.
- But the most powerful thing is that list need not be always homogeneous.
- A single list can contain strings, integers, as well as objects.
- Lists can also be used for implementing stacks and queues.
- Lists are mutable, i.e., they can be altered once declared.
Declaring a list:
L = [1, "a" , "string" , 1+2] print(L) ## output : [1, 'a', 'string', 3]
Homogeneous & Non-Homogeneous List
Homogeneous List contains all elements of same data type.
Non- Homogeneous List contains elements of different data type.
l = [ 'hello','hi','how are you' ] print(l) print(l[2]) l = [ 56,23,45,12,67,12,43,1,6,8,6,33,12] print("Homogeneous List :",l) print(l[5]) l = [ 'hello','hi', 3, 4.5 ] print("Non-Homogeneous List : ",l) print(l[-3]) ## output: ## ['hello', 'hi', 'how are you'] ## how are you ## Homogeneous List : [56, 23, 45, 12, 67, 12, 43, 1, 6, 8, 6, 33, 12] ## 12 ## Non-Homogeneous List : ['hello', 'hi', 3, 4.5] ## hi
Tuple
- A Tuple is a collection of Python objects separated by commas.
- In someway a tuple is similar to a list in terms of indexing, nested objects, and repetition but a tuple is immutable, unlike lists which are mutable.
Declaring a Tuple
tup = 'python', 'gyansetu' print(tup) ## output: ('python', 'gyansetu')
### Another way for doing the same tup = ('python', 'gyansetu') print(tup) ## output: ('python', 'gyansetu')
Dictionary
- It consists of key-value pairs.
- The value can be accessed by a unique key in the dictionary.
Dictionary Example with Key-Value pair
mydict = { 'name':'python', 'build_year':1991, 'Father of Python':"Guido Van Rossum", 'Frame_works':['Django','Flask','Web2PY','Torando','kivi'], 'versions' : [1.0,2.0,3.0], 'latest_version':3.6} print(mydict) print("Name : ", mydict['name']) #returns the value of the key 'name' print("Frame Works : ", mydict['Frame_works']) ## output: ## {'name': 'python', 'build_year': 1991, 'Father of Python': 'Guido Van Rossum', 'Frame_works': ['Django', 'Flask', 'Web2PY', 'Torando', 'kivi'], 'versions': [1.0, 2.0, 3.0], 'latest_version': 3.6} ## Name : python ## Frame Works : ['Django', 'Flask', 'Web2PY', 'Torando', 'kivi']
Operators in Python
Arithmetic Operators
Arithmetic operators are used to performing mathematical operations like addition, subtraction, multiplication, and division
- Addition Operator ( + )
- Subtraction Operator ( – )
- Multiplication Operator ( * )
- Division Operator ( / )
- Modulas Operator ( % )
- Floor Division ( // )
- Exponent Operator ( ** )
Example of Arithmetic Operator
x = 10 y = 3 z1 = x+y z2 = x-y z3 = x * y print("Addition of {} and {} is {}.".format(x,y,z1)) print("Subtraction of {} and {} is {}.".format(x,y,z2)) print("Multiplication of {} and {} is {}.".format(x,y,z3)) ## output: ## Addition of 10 and 3 is 13. ## Subtraction of 10 and 3 is 7. ## Multiplication of 10 and 3 is 30.
Comparison Operators
These operators compare the values on either side of them and decide the relation among them.
- Less Than ( < )
- Less Than Equals To ( <= )
- Greater Than ( > )
- Greater Than Equals To ( >= )
- Equals To Equals To ( == )
- Not Equals To ( != )
Example of Comparison Operator
#returns true if statement is True else returns False print("6 < 8 ", 6 < 8) ## output: True print("6 <= 6 ", 6 <= 6) ## output: True print("5 > 6 ", 5 > 6) ## output: False print("6 != 7 ", 6 != 7) ## output: True
Logical Operators
Logical operators are used on conditional statements (either True or False). They perform Logical AND, Logical OR, and Logical NOT operations
- And
If x is false, return x
else return y
- Or
If x is false, return y
else x
Examples:
print( 5>7 and 6-5*3+6) ## output: False print( 6-4*3+6 and 5>7) ## output: 0 print( 6-4*3+6 or 6 > 5) ## output: True print( 6 > 5 or 6-4*3+6) ## output: True
Membership Operator
Membership operators are operators used to validate the membership of a value. It test for membership in a sequence, such as strings, lists, or tuples.
- in
- not in
Examples:
s2 = "Dog is an animal." s1 = "Dog" x = s1 in s2 if x : print("Pattern Found in step 1") #return this if x=True else : print("Patten Not Found") p = s1 not in s2 print(x) print(p) ## OUTPUT: ## Pattern Found in step 1 ## True ## False
Identity Operator
Python Membership and Identity Operators · in operator: The ‘in’ operator is used to check if a value exists in a sequence or not.
- is
- is not
Examples:
x = 5 y = 5 print(x is y) print( x is not y ) p = 3 q = 4 if p is q : print("Both are equal") else : print("Both are different")
Conditional Statements
In programming and scripting languages, conditional statements or conditional constructs are used to perform different computations or actions depending on whether a condition evaluates to true or false. (Please note that true and false are always written as True and False in Python.)
Example to calculate the greatest of 3 numbers using a conditional statement
#Greatest among Three numbers a = int(input("A : ")) b = int(input("B : ")) c = int(input("C : ")) if a >= b : if a >= c : print("A is greatest ") else : print("C is greatest ") elif b >= c : print("B is Greatest") else : print("C is Greatest ") ## OUTPUT: ## A : 12 ## B : 32 ## C : 16 ## B is Greatest
Loops in Python
Loops can be divided into 2 kinds.
- Finite: This kind of loop works until a certain condition is met
- Infinite: This kind of loop works infinitely and does not stop ever.
There are 2 kinds of loops:
- for
- while
For Loops: These loops are used to perform a certain set of statements for a given condition and continue until the condition has failed. You know the number of times that you need to execute the for loop.
Example of For loop
print("List Iteration") l = ["books", "bags", "pens"] for i in l: print(i) ## OUTPUT: ## List Iteration ## books ## bags ## pens
For loop using range()
for i in range(5): print(i) ## OUTPUT: ## 0 ## 1 ## 2 ## 3 ## 4
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