Introduction

Python is a programming language which is:

1. Easy to learn

   • simple syntax

   • easy to setup

2. Large ecosystem

   • many libraries

   • large community

3. Flexible

   • you are not limited to language specifics

What Python is used for:

• Web Development

• Data Science

• Machine Learning

• Artificial Intelligence

• Web Scrapping

• Automation

  • Like automating DevOps tasks

  • Automating general tasks

Why Python with DevOps?

As an approach to culture, platform, and automation, Python is an important language for DevOps engineers or teams working to automate repetitive tasks, infrastructure management, provisioning, API driven deployment.

Setup python locally in Ubuntu

Head over to the official Python website and download the latest version of it according to your operating system.

Check that the Python is downloaded to your machine:

# this comamand is for Linux users
python3

# Checking the Python Path
which python3

Python Fundamentals:

Print Function

The print() function in Python is used to output text or other data to the console.

1. objects: Any number of objects to be printed. Multiple objects are separated by a space by default.

2. sep: A string inserted between each object. The default is a space.

3. end: A string appended after the last object. The default is a newline.

4. file: A file-like object (stream). The default is sys.stdout.

# Basic usage
print("Hello, world!")

# Printing multiple items
print("The answer is", 42)

# Changing the separator
print("apple", "banana", "cherry", sep=", ")

# Changing the end character
print("Hello", end=" ")
print("world!")

# Printing to a file
with open("output.txt", "w") as f:
    print("Hello, file!", file=f)

# This is the Output: Hello, file!

# Using formatted strings aka f-strings
name = "Alice"
age = 30
print(f"My name is {name} and I am {age} years old.")

Literals

A literal is a notation for representing a fixed value directly in the source code. Here is an example of a literal:

# Integer Literal:
93
# Floating-point Literal:
3.14
# String Literal:
"Hello, Suraj!"
# Boolean Literal
True
# None Literal: This represents the absesce of a value or null value
None
# Lits Literal:
[1,2,3,4]

# Simple program for literals
integer_literal = 42
string_literal = "Hello"
print(integer_literal, string_literal)

Variable

A variable is a named storage location in memory that holds a value that can be changed during program execution.

Variable Rules in Python

1. Names can contain letters, digits, and underscores: e.g., my_variable1.

2. Names must start with a letter or an underscore: e.g., _variable or variable1.

3. Names cannot start with a digit: e.g., 1variable is invalid.

4. Names are case-sensitive: e.g., Variable and variable are different.

5. Cannot use Python reserved keywords: e.g., class, def, if, etc.

Naming Convention:
Naming conventions is a convention(generally agreed scheme) for naming variables.

• Use lowercase with words separated with Underscores

# Simple program using variables
my_number1 = 10
my_number2 = 20
print("First No.", my_number1, "Second No.", my_number2)

Keywords

Keywords in Python are reserved words that have special meaning and cannot be used as identifiers (variable names, function names, etc.). You don't need to remember all these keywords I just put it over here for reference.

Expressions and statements

Expressions are code segments that evaluate a value, while statements are instructions that perform an action in a program. A program is made up of several statements.

# These are the exmaple of Expressions:

# 1. Arithmetic expression:
2+3
# 2. String concatination
"Hello, "+" World!"
# 3. Function call expression:
len("example")
# 4. Boolean expression:
5>2
# List indexing:
my_list[1]

# Simple program with expressions and statements

a = 5  # this is a statement (assignment statement with an expression on the right side)
b = 10  # this is a statement (assignment statement with an expression on the right side)
result = a + b  # this is a statement (assignment statement with an expression on the right side)
print("Result:", result)  # this is a statement (function call statement with an expression as an argument)

Comments

Comments in Python are used to explain code logic, making it easier for others to understand what the code does. It also helps to document the code’s purpose, usage, and functionality and enhances maintainability by making the code simpler to manage and update.

Comments are of two types:

1. Simple Line Comments that start with '#' and below is an example.

x = 10  # Assigning 10 to x
print(x)  # Printing the value of x

2. Multi-line Comments: that uses triple quotes (''' or """).

"""
This is a multi-line comment.
Hi there suraj this side.
"""

Indentation in Python

Indentation means spacing in statements in Python is very important. For example, in below code snippet below, you can see the print function has a lot more space from its original position which will give an IndentationError: unexpected indent .

# This program will give indentation error
name = "Suraj"
   print(name)

Data Types

Different data types can do different things: We will see two immutable data types in this blog rest of all we'll learn in the journey...

Number Data Types

# Simple program with number data types
pi = 3.14
print("Pi:", pi)

# Output: 3.14

Strings Data Types

# Simple program with strings
message = "Hello, Python!"
print(message)

String Concatenation

Adding strings together.

# String Concatenation program
print("Hello Suraj" + "Are you learning Python?") # we concatenate using '+' symbol

Instead of writing above style, we can usef-string:

# This is a formatted string literal, introduced in Python 3.6
print(f"Hello Suraj, are you {21} years old?")

# Output:
Hello Suraj, are you 21 years old?

String Methods

String methods...

1. upper(): Used to convert all characters in a string to uppercase.

      # Convert to uppercase
      message = "hello, python!"
      print(message.upper())
   
      # Output:
      HELLO, PYTHON!
   

2. lower(): Convert all characters in a string to lowercase.

    # Convert to lowercase
    message = "HELLO, PYTHON!"
    print(message.lower())
   
    # Output:
    hello, python!
   

3. strip(): Remove leading and trailing whitespace.

    # Remove whitespace
    message = "   hello, python!   "
    print(message.strip())
   
    # Output:
    hello, python!
   

4. replace(): Replace a substring with another substring.

    # Replace substring
    message = "hello, python!"
    print(message.replace("python", "world"))
   
    # Output:
    hello, world!
   

5. split(): Split a string into a list of substrings.

    # Split string into list
    message = "hello, python!"
    words = message.split()
    print(words)
   
    # Output:
    ['hello,', 'python!']
   

6. join(): Join elements of a list into a string.

    # Join list into string
    words = ["hello", "python"]
    message = " ".join(words)
    print(message)
   
    # Output:
    hello python
   

7. find(): Find the first occurrence of a substring.

    # Find substring
    message = "hello, python!"
    position = message.find("python")
    print("Position of 'python':", position)
   
    # Output:
    Position of 'python': 7
   

8. count(): Count the number of occurrences of a substring.

    # Count occurrences of substring
    message = "hello, python! python is fun!"
    count = message.count("python")
    print("Occurrences of 'python':", count)
   
    # Output:
    Occurrences of 'python': 2
   

9. capitalize(): Capitalize the first character of the string.

    # Capitalize first character
    message = "hello, python!"
    print(message.capitalize())
   
    # Output:
    Hello, python!
   

10. title(): Capitalize the first character of each word.

    # Capitalize first character of each word
    message = "hello, python!"
    print(message.title())
    
    # Output:
    Hello, Python!
    

11. swapcase(): Swap the case of all characters in the string.

    # Swap case of characters
    message = "Hello, Python!"
    print(message.swapcase())
    

Escaping Characters

Escaping characters in Python allows you to include special characters in strings that would otherwise be difficult or impossible to include directly. This is done using a backslash (\) followed by the character you want to escape.

# 1. Using a newline character(\n)
print("Hello\nSuraj")
#Output:
Hello
Suraj

# 2. Tab Character(\t)
print("Hell0\tSuraj")
# Output:
Hello    Wolrd

# 3. Backslash Character(\\)
print("This is a backslash: \\")
# Output:
This is a backslash: \ # This is the output because, The \\ sequence inserts a single backslash.

# 4. Single Qoute(\') and Double Qoute(\")
print('I said, \'This is single qoute!\'')
print("I said, \"This is double qoute!\"")
# Output:
He said, 'Hello, World!'
He said, "Hello, World!"

# 5. Carriage Return(\r)
print("Hello\rBro")
# Output:
Bro # The \r character moves the cursor to the beginning of the line, so "Bro" overwrites "Hello.

# 6. Bell/Alert(\a)
print("Hello\aBro")
# Output: You might hear a beep sound, and the text "HelloBro" will be printed. BecauseThe \a character triggers the system bell (alert).

String Characters & Slicing

A string is a sequence of characters. Each character in a string can be accessed using its index. Python strings are zero-indexed, meaning the first character has an index 0, the second character has an index 1, and so on.

text = "Python"
print(text[0])  # Output: P
print(text[1])  # Output: y
print(text[-1]) # Output: n (negative indexing starts from the end)

String Slicing

String slicing allows you to extract a portion of a string by specifying a start and end index. The syntax for slicing is: string[start:stop:step]

Examples of Slicing

# Basic Slicing
text = "Python"
print(text[1:4])  # Output: yth

# Omitting Start or Stop
text = "Python"
print(text[:4])  # Output: Pyth (Omits the start index, starts from the beginning)
print(text[2:])  # Output: thon (Omits the end index, goes till the end)

# Using Step
text = "Python"
print(text[::2])  # Output: Pto (Takes every 2nd character)

# Negative Indices and Slicing
text = "Python"
print(text[-5:-1])  # Output: ytho (From index -5 to -2, -1 is not included)
print(text[::-1])   # Output: nohtyP (Reverses the string)

# Reversing a String
text = "Python"
reversed_text = text[::-1]
print(reversed_text)  # Output: nohtyP

Booleans

# Simple program with booleans
is_active = True
print("Is active:", is_active)

# Output:

Build-In Functions

# Simple program using built-in functions
message = "Hello, Python!"
print("Length of message:", len(message))

# Output:

Enums

from enum import Enum

# Define an enum for days of the week
class Day(Enum):
    MONDAY = 1
    TUESDAY = 2
    WEDNESDAY = 3
    THURSDAY = 4
    FRIDAY = 5
    SATURDAY = 6
    SUNDAY = 7

# Accessing enum members
print(Day.MONDAY)            # Output: Day.MONDAY
print(Day.MONDAY.name)       # Output: MONDAY
print(Day.MONDAY.value)      # Output: 1

# Iterating over enum members
for day in Day:
    print(day.name, day.value)

# this is the Output:
"""
MONDAY 1
TUESDAY 2
WEDNESDAY 3
THURSDAY 4
FRIDAY 5
SATURDAY 6
SUNDAY 7
"""

User input

# Simple program with user input
name = input("Enter your name: ")
print(f"Hello, {name}")

# Output:
# Enter your name: Suraj # In console
# Hello, Suraj # actual output after entring name

Logic and Bit operators

Operators

# Simple program with operators
result = 10 + 5
print("Result of addition:", result)Logic and Bit operators

Operators

# Simple program with operators
result = 10 + 5
print("Result of addition:", result)

# Output:

Arithmetic Operators

# Simple program with arithmetic operators
quotient = 10 / 2
print("Quotient:", quotient)

# Output:

Comparison Operators

# Simple program with comparison operators
is_equal = (10 == 10)
print("10 is equal to 10:", is_equal)

# Output:

Boolean Operators

# Simple program with boolean operators
result = True and False
print("True and False:", result)

# Output:

Bitwise Operators

# Simple program with bitwise operators
bitwise_result = 5 & 3
print("5 AND 3:", bitwise_result)

# Output:

is & in Operators

# Simple program with 'is' and 'in' operators
x = 5
y = 5
is_same = (x is y)
contains = 'a' in 'apple'
print("x is y:", is_same)
print("'a' in 'apple':", contains)

# Output:

Ternary Operator

# Simple program with ternary operator
x = 10
result = "Even" if x % 2 == 0 else "Odd"
print("x is:", result)

# Output

Control Flow - Conditional Blocks & Loops:

Conditional Statements:

if Statement: Executes a block of code if a specified condition is true.

# Simple if statement
x = 10
if x > 0:
    print("Positive")

# Output:
Positive

if-else Statement: Executes one block of code if a condition is true, and another block of code if the condition is false.

# Simple if-else statement
x = -5
if x > 0:
    print("Positive")
else:
    print("Non-positive")

# Output
Non-positive

if-elif-else Statement: Executes different blocks of code based on multiple conditions.

# Simple if-elif-else statement
x = 0
if x > 0:
    print("Positive")
elif x < 0:
    print("Negative")
else:
    print("Zero")

# Output:
Zero

Loops:

while Loop: Repeats a block of code as long as a specified condition is true.

# Simple while loop
count = 1
while count <= 5:
    print("Count:", count)
    count += 1

# Output:
Count: 1 
Count: 2 
Count: 3 
Count: 4 
Count: 5

for Loop: Iterates over a sequence (such as a list, tuple, or string).

# Simple for loop
for i in range(5):
    print("Iteration:", i)

# Output:
Iteration: 0
Iteration: 1
Iteration: 2
Iteration: 3
Iteration: 4

Arithmetic Operators

# Simple program with arithmetic operators
quotient = 10 / 2
print("Quotient:", quotient)

Comparison Operators

# Simple program with comparison operators
is_equal = (10 == 10)
print("10 is equal to 10:", is_equal)

Boolean Operators

# Simple program with boolean operators
result = True and False
print("True and False:", result)

Bitwise Operators

# Simple program with bitwise operators
bitwise_result = 5 & 3
print("5 AND 3:", bitwise_result)

# Output:

is & in Operators

# Simple program with 'is' and 'in' operators
x = 5
y = 5
is_same = (x is y)
contains = 'a' in 'apple'
print("x is y:", is_same)
print("'a' in 'apple':", contains)

# Output:

Ternary Operator

# Simple program with ternary operator
x = 10
result = "Even" if x % 2 == 0 else "Odd"
print("x is:", result)

# Output

Control Flow - Conditional Blocks & Loops:

Conditional Statements:

1. if Statement: Executes a block of code if a specified condition is true.

    # Simple if statement
    x = 10
    if x > 0:
        print("Positive")
   
    # Output:
    Positive
   

2. if-else Statement: Executes one block of code if a condition is true, and another block of code if the condition is false.

    # Simple if-else statement
    x = -5
    if x > 0:
        print("Positive")
    else:
        print("Non-positive")
   
    # Output
    Non-positive
   

3. if-elif-else Statement: Executes different blocks of code based on multiple conditions.

    # Simple if-elif-else statement
    x = 0
    if x > 0:
        print("Positive")
    elif x < 0:
        print("Negative")
    else:
        print("Zero")
   
    # Output:
    Zero
   

Loops:

1. while Loop: Repeats a block of code as long as a specified condition is true.

    # Simple while loop
    count = 1
    while count <= 5:
        print("Count:", count)
        count += 1
   
    # Output:
    Count: 1 
    Count: 2 
    Count: 3 
    Count: 4 
    Count: 5
   

for Loop: Iterates over a sequence (such as a list, tuple, or string).

# Simple for loop
for i in range(5):
    print("Iteration:", i)

# Output:
Iteration: 0
Iteration: 1
Iteration: 2
Iteration: 3
Iteration: 4

Thanks for reading...