Table of Contents

• Installation
  • How to install python
• Comment
• Operators
  • Logical operators
  • Bitwise operators
  • Arithmetic operators
  • Comparison operators
  • Assignment operators
• Conditional structures
  • Ternary Operators
• Data types
  • How to check data type
  • String
  • List
  • Dictionary
  • Set
• map() Function
• filter() Function
• reduce() Function
• zip() Function
• format() function
• Miscellaneous
  • Get the number of bits in an integer in binary, excluding the sign and leading zeros.
  • Swap two variables in one line
• Books and other resources
• Bug Reports and Feature Requests
• Author
• License

Installation

How to install python

If you don't want to install python natively you can use docker.

docker run -it --rm python:latest
# check which version of python you're running
python --version

Comment

# single line comment

# begin
# multiline
# comment
# end

or

"""
begin
multiline
comment
end
"""

Operators

Logical operators

Bitwise operators

Arithmetic operators

Comparison operators

Assignment operators

Conditional structures

x = 11
if x > 10:
    print("The number is greater than 10")
else:
    print("The number is not greater than 10")

if x == 10:
    print('The value of x is 10')
elif x == 11:
    print('The value of x is 11')
else:
    print('The value of x is not either 10 or 11')

Ternary Operators

execute_if_true if condition else execute_if_false

print "even" if 6 % 2 == 0 else "odd"

# output
# even

Data types

Further readings

How to check data type

a = 37
isinstance(a, int)
# True
isinstance(a, float)
# False

type(10)
# <type 'int'>

String

print('Hello World'[0])
# H
print('Hello World'[1])
# e

List

a = ["a", "b", "c"]

f, s, t = ["a", "b", "c"]
# output
# f = 'a'
# s = 'b'
# t = 'c'

f, *mid, l = ["a", "b", "c"]

# output
# f = 'a'
# mid = ['b']
# l = 'c'

a = ["a", "b", "c"]
b = ["d", "e", "f"]

a.append(b)
# output
# ['a', 'b', 'c', ['d', 'e', 'f']]

a = ["a", "b", "c"]
b = ["d", "e", "f"]

a.extend(b)
# output
# ['a', 'b', 'c', 'd', 'e', 'f']

List slice

list[start_index:stop_index:step]

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

numbers[0::2]

# output
# [1, 3, 5, 7, 9]


numbers[1::2]

# output
# [2, 4, 6, 8, 10]

List Comprehensions

Create a list of lists

[[0]*2 for i in range(2)]

# output
# [[0, 0], [0, 0]]

Create a list of variable length of lists

n = 10
[[0]*(i+1) for i in range(n)] + [[0]*i for i in range(n-1, 0, -1)]

# output
# [[0],
# [0, 0],
# [0, 0, 0],
# [0, 0, 0, 0],
# [0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0, 0],
# [0, 0, 0, 0, 0],
# [0, 0, 0, 0],
# [0, 0, 0],
# [0, 0],
# [0]]

Create a matrix of multiplication tables

n = 5
[[i*j for i in range(1,n+1)] for j in range(1, n+1)]

# output
# [[1, 2, 3, 4, 5],
# [2, 4, 6, 8, 10],
# [3, 6, 9, 12, 15],
# [4, 8, 12, 16, 20],
# [5, 10, 15, 20, 25]]

Dictionary

Dictionary Comprehensions

{c: ord(c) - 96 for c in string.ascii_lowercase[:26]}

# output
# {'a': 1, 'c': 3, 'b': 2, 'e': 5, 'd': 4, 'g': 7, 'f': 6, 'i': 9, 'h': 8, 'k': 11, 'j': 10, 'm': 13, 'l': 12, 'o': 15, 'n': 14, 'q': 17, 'p': 16, 's': 19, 'r': 18, 'u': 21, 't': 20, 'w': 23, 'v': 22, 'y': 25, 'x': 24, 'z': 26}

Set

Set Comprehensions

numbers = [2, 2, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 11, 12, 13, 14]
uniqueEvenNumbers = {num for num in numbers if num % 2 == 0}

# output
# set([2, 4, 6, 8, 10, 12, 14])

uniqueNumbers = set(numbers)

# output
# set([2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14])

map() Function

map(function, list)

numbers = [1, 2, 3, 4, 5]
squared = list(map(lambda n: n*n, numbers))

# output
# [1, 4, 9, 16, 25]

filter() Function

filter(function, list)

numbers = [1, 2, 3, 4, 5]
odd = list(filter(lambda n: n % 2 != 0, numbers))

# output
# [1, 3, 5]

reduce() Function

reduce(function, list)

numbers = [1, 2, 3, 4, 5]
sum = reduce(lambda x, y: x + y, numbers

# output
# 15

zip() Function

Creates an iterator of tuples.

zip(iterator1, iterator2, iterator3 ...)

a = ['a', 'b', 'c']
b = [1, 2, 3]

zip(a, b)

# output
# [('a', 1), ('b', 2), ('c', 3)]

tuples to list

list(map(list, zip(a, b)))

# output
# [['a', 1], ['b', 2], ['c', 3]]

format() function

"{:{width}.{prec}f}".format(10.344, width=10, prec=6)

# output
# ' 10.344000'

Miscellaneous

Get the number of bits in an integer in binary, excluding the sign and leading zeros.

n.bit_length()

Swap two variables in one line

a, b = b, a

My Python Articles

1. How To Run a Python Script Using a Docker Container
2. How To Create a Twitter Bot in Python
3. How To Extract Text From Images Using Tesseract OCR Engine and Python
4. How to Connect to a PostgreSQL Database With a Python Serverless Function
5. How to Deploy a Python Serverless Function to Vercel
6. How to Dockerize an Existing Flask Application
7. How To Create a Docker Image From a Container

Books and other resources

1. TODO

Bug Reports and Feature Requests

Please create an issue with as much information you can. Thank you.

Author

Mahbub Zaman (https://mahbub.ninja)

License

MIT License