Python --> by myCODEnotein

Variables and Constants

Constants

Variables

Rules for naming Variables

Character Set In Python

What is a character set ?

Character set used In Python

Similarly

Tokens in python

Keywords

# To get a list of Keywords run :
help("keywords")

# List of Keywords:
keywords = ["False", "None", "True", "__peg_parser__", "and", "as", "assert", "async", "await", "break", "class", "continue", "def", "del", "elif", "else", "except", "finally", "for", "from", "global", "if", "import", "in", "is", "lambda", "nonlocal", "not", "or", "pass", "raise", "return", "try", "while", "with", "yield"]

# Note:
# you can also run: 
help()
# and then type keywords

Literals

# Literals are fixed values
Examples of literals:

Numerical Literals # ex: 1(int) , 2.5(float)
String Literals # ex: "amit sir","Vikas","myCODEnotein"
Boolean Literals # ex: True , False
None
#True,False and None are keywords also.

Identifiers

Identifiers are names used to identify a piece of data like variables,name of functions,name of classes

You can also say that all keywords are also Identifiers

Rules for defining vaiables= Rules for defining Identifiers

Punctuators

Operators

# Arithmetic Operators
op: + , - , * , / , // , % , **

# The operator is known as exponential operator
for ex: 2**5
is read as: 2 raise to the power 5 (25) 
returns: 32

# Operator is known as floor-division operator
for ex: 9//4
returns: 2 (/ operator returns 2.25) 
desc: returns largest-integer , smaller than quotient

# Operator is known as modulus operator
for ex: 3%5 
returns: 3 (remainder got by dividing 3 by 5) 
desc: returns remainder

Quick Functions

Dir Function

Help Function

help(argument)
# argument can be any function or class or module name
# returns a description of the given argument

Input Function

name = input("message to display")
# Used to take user input , obviously

Enumerate

# Used to get index and value while using for a loop
# Let us understand enumerate by example
for index,value in enumerate(list_of_values): 
	# Code Here 
	print(index,value)

All and Any Functions

# Let there be a list
myList = [5>0 , 6<0 , 1==0]

all(myList)==True # only if all conditions are True
# In this case all(myList) = False

any(myList)==True # even if one condition is True
# In this case any(myList) = True

Split and Strip functions

# For example:
a = "Hello world my name is vikas"
a = a.split(" ")
# Now a=["Hello","world","my","name","is","vikas"]

# For example:
a = "     myCODEnotein  is    best     "
a = a.strip() 
# Now a="myCODEnotein  is    best"

Generators in python (yield keyword)

What are generators?

How to create a generator?

# Example function
def myFunction(range_of_number):
	for x in range(range_of_number):
		# your code 
		yield(x) 
		# x can be replaced by the value which you want to return
'''
Now this function is a generator
'''

How to use a generator?

# Example function
def create_square(list_of_numbers):
	for number in list_of_numbers:
		yield(number*number)

# Now to use the create_square function
squared_list = create_square([1,2,3,4,5])

# First way
# You can use next function 
next(squared_list) # returns sqaure of 1
'''
If you run it again it will return sqaure of 2
If you run it again it will return sqaure of 3
and so on till last element.
After that it will return Error.
'''

# Second way
# Using for loop
for square in squared_list:
	print(square)

Creating a mini server with python

python -m http.server port_number
# by default port_number is 8000

#For example:
python -m http.server
#(or)
python -m http.server 8000

Opening the server at a specific address

python -m http.server port_number --bind address

# For example
python -m http.server 8000 --bind 127.0.0.1
# 127.0.0.1 is by default 
# and there is no need to write 8000 as well

Opening the server in a particular directory

python -m http.server --directory path

# For example
python -m http.server --directory C://myCODEnotein