Python Notes

Notes from multiple learning sources. Thank you all.

Ref links:

• Chai aur python
• Google IT Automation with Python Certificate

Few of the best python book:

• Python Crash Course ref youtube link
• Python Programming By John Zelle
• Algorithms Illuminated - Path1: The Basics - By Tim Roughgarden (Not in python, but fir Algo.
• Python Tools for Scientiest.
• Effective Panda

Chapter1

hello_chai.py

Creating a function, that can be used from a different file.

print("chai aur python")

def chai(n):
  print(n)

chai("lemon tea")

chai_one = "lemon tea"
chai_two = "ginger tea"
chai_three = "masala chai"

chai.py

Calling a function from anoher file

from hello_chai import chai

chai("ginger tea")

# this is comment

Knowing what are the functions, variables with in a module

• import myModule

• dir(myModule)

• you can also use as from myModule import aGivenFunction

Note: 001

print("Hello"+"Python") # output: HelloPython (No space when we use +)
print("Hello", "Python") #Output: Hello Python (When we use , it add a space in between these two string.)

Note: 002

print("My age is" , 36) # This will work. As we are not doing any concanitation. ( So, good to use , ) 

print("My age is " + 36)  # This will give you error: "TypeError: must be str, not int"  # + expect both to be string.

Using + works for combining two strings — it concatenates them. It also works for two numbers — it adds the numbers together.

But, it can't join a string and a number.

• This both will work. In comma, we don't need to add space.
• In the second one we are using +, but giveing a space at the end of is, and using "27" as string.

print("My age is" , 27)
print("My age is " + "27")

print("Our combined age is 27" + "32") # output: Our combined age is 2732

Note: 003

seconds = 14926

hours = seconds//3600

minutes = (seconds - hours * 3600)//60

final_seconds = seconds%60

print(str(seconds) , "seconds is the same as")
print(str(hours) , "hours," , minutes  , "minutes, and" , final_seconds , "seconds")

seconds = 14926

hours = seconds // 3600

leftover_seconds = seconds % 3600

minutes = leftover_seconds // 60

final_seconds = leftover_seconds % 60

print(str(seconds) , "seconds is the same as")
print(str(hours) , "hours," , minutes  , "minutes, and" , final_seconds , "seconds")

Note: 004

Naming convention

• Class names start with an Uppercase
• Other identifiers start with lowercase
• starting with single _ : private identifier
• starting with double __ : strongly private
• start and end with double __ : language defined special name.

Note: 005 : set

Example of set: set_a = {1,2,3} print(set_a) # output: {1,2,3}

set_b = {1,2,2,4} print(set_b) # output: {1,2,4}

Note: 006 : Arithmetic Operators

• Addition: a + b
• Subtraction: a - b
• Multiplication: a * b
• Division: a / b
• Modulus: a % b
• Exponent: a ** b
• Floor Division: a // b

Note: 007: Assignment Operators

Note: 008 : Comparison Operators

• Equal to: a == b
• Not Equal to: a != b
• Greater than: a > b
• Less than: a < b
• Greater than equal to: a >= b
• Less Than Equal to: a <= b

Note: 009 : Assignment Operators

• Assigns value from right to left: a = b
• a += b ( a = a + b )
• a -= b
• a *= b
• a /= b
• a ** = b
• a //= b

Note: 010: Logical Operators:

• a and b
• a or b
• not a

Note: 011: Bitwise Operators:

• Binary AND: a & b
• Binary OR: a | b
• Bianry XOR: a ^ b
• Binary NOT: a ~ b
• Binary left shift: a <<
• Binary Right Shift: a >> b

Identity Operators:

• is: Evaluates to TRUE, if the variables on either side of the operator points to the same objects and FALSE otherwise.
• is not:

Note: 012: Membershif Operators: