1. Variables and Data Types:

• variable_name = value: Declare and assign a value to a variable.

• int, float, str, bool: Data types for integers, floating-point numbers, strings, and booleans.

• type(variable): Check the data type of a variable.

Example:

x = 5

name = "John"

is_true = True

print(type(x))    # Output: <class 'int'>

print(type(name)) # Output: <class 'str'>

print(type(is_true)) # Output: <class 'bool'>

2. Basic Input and Output:

• print("text"): Display text or variable values.

• input("prompt"): Accept user input.

Example:

name = input("Enter your name: ")

print("Hello, " + name + "!")

# Output:

# Enter your name: John

# Hello, John!

3. Operators:

• Arithmetic Operators: +, -, *, /, //, %, **.

• Assignment Operators: =, +=, -=, *=, /=, //=, %=, **=.

• Comparison Operators: ==, !=, >, <, >=, <=.

• Logical Operators: and, or, not.

Example:

x = 5 + 3

y = x * 2

z = y > 10 and x < 5

print(x) # Output: 8

print(y) # Output: 16

print(z) # Output: False

4. Conditional Statements:

• if statement: Execute a block of code if a condition is true.

• elif statement: Execute a block of code if the previous condition(s) are false and this condition is true.

• else statement: Execute a block of code if all previous conditions are false.

• ==, !=, >, <, >=, <=: Comparison operators used in conditions.

Example:

age = 18

 if age >= 18:

    print("You are an adult.")

elif age >= 13:

    print("You are a teenager.")

else:

    print("You are a child.")

# Output: You are an adult.

5. Loops:

• for loop: Execute a block of code a specific number of times.

• while loop: Execute a block of code as long as a condition is true.

• range(start, stop, step): Generate a sequence of numbers.

• break: Exit the loop prematurely.

• continue: Skip the current iteration and move to the next one.

Example:

# for loop

for i in range(1, 6):

    print(i)

# Output: 1 2 3 4 5

# while loop

count = 0

while count < 5:

    print(count)

    count += 1

# Output: 0 1 2 3 4

6. Lists:

• my_list = [item1, item2, item3]: Create a list.

• len(my_list): Get the length of a list.

  • index = my_list.index(item): Find the index of an item in a list.

  • my_list.append(item): Add an item to the end of a list.

  • my_list.insert(index, item): Insert an item at a specific index in a list.

  • my_list.pop(): Remove and return the last item from a list.

  • my_list.remove(item): Remove the first occurrence of an item from a list.

Example:

numbers = [1, 2, 3, 4, 5]

print(len(numbers))  # Output: 5

print(numbers.index(3))  # Output: 2

numbers.append(6)

print(numbers)  # Output: [1, 2, 3, 4, 5, 6]

numbers.insert(2, 10)

print(numbers)  # Output: [1, 2, 10, 3, 4, 5, 6]

last_item = numbers.pop()

print(last_item)  # Output: 6

print(numbers)  # Output: [1, 2, 10, 3, 4, 5]

numbers.remove(3)

print(numbers)  # Output: [1, 2, 10, 4, 5]

7. Strings:

• my_string = "text": Create a string.

• len(my_string): Get the length of a string.

• my_string.upper(): Convert a string to uppercase.

• my_string.lower(): Convert a string to lowercase.

• my_string.strip(): Remove leading and trailing whitespace.

• my_string.split(separator): Split a string into a list of substrings.

• my_string.replace(old, new): Replace occurrences of a substring in a string.

Example:

message = "Hello, World!"

print(len(message))  # Output: 13

print(message.upper())  # Output: HELLO, WORLD!

print(message.lower())  # Output: hello, world!

name = "   John   "

print(name.strip())  # Output: John

sentence = "I love Python programming"

words = sentence.split(" ")

print(words)  # Output: ['I', 'love', 'Python', 'programming']

replaced = sentence.replace("Python", "JavaScript")

print(replaced)  # Output: I love JavaScript programming

8. Functions:

• def function_name(parameters): Declare a function.

• return value: Return a value from a function.

• function_name(arguments): Call a function with arguments.

Example:

def greet(name):

    return "Hello, " + name + "!"

message = greet("John")

print(message)  # Output: Hello, John!

9. File Handling:

• open(filename, mode): Open a file.

• file.read(): Read the contents of a file.

• file.write(text): Write text to a file.

• file.close(): Close a file.

Example:

# Open a file in read mode

file = open("data.txt", "r")

contents = file.read()

print(contents)

file.close()

# Open a file in write mode

file = open("output.txt",

10. Modules for File Operations:

• os: Module for interacting with the operating system.

  • os.getcwd(): Get the current working directory.

  • os.listdir(path): Get a list of files and directories in a given path.

  • os.path.join(path, filename): Join a path and a filename to create a file path.

• shutil: Module for high-level file operations.

  • shutil.copy(source, destination): Copy a file from source to destination.

  • shutil.move(source, destination): Move or rename a file.

Example:

import os

import shutil

current_dir = os.getcwd()

print(current_dir)  # Output: Current working directory

files = os.listdir(current_dir)

print(files)  # Output: List of files and directories in the current directory

file_path = os.path.join(current_dir, "file.txt")

print(file_path)  # Output: Full file path

shutil.copy("source.txt", "destination.txt")  # Copy file from source to destination

shutil.move("old.txt", "new.txt")  # Move or rename a file

11. Virtual Environments:

• python -m venv env_name: Create a virtual environment.

• source env_name/bin/activate (Linux/Mac) or .\env_name\Scripts\activate (Windows): Activate a virtual environment.

• deactivate: Deactivate the current virtual environment.

Example:

python -m venv myenv  # Create a virtual environment

source myenv/bin/activate  # Activate the virtual environment

# Your Python environment is now isolated within the virtual environment

deactivate  # Deactivate the virtual environment

12. Working with Dates and Times:

• datetime: Module for working with dates and times.

  • datetime.now(): Get the current date and time.

  • datetime.date(): Get the current date.

  • datetime.time(): Get the current time.

Example:

from datetime import datetime

current_datetime = datetime.now()

print(current_datetime)  # Output: Current date and time

current_date = datetime.date()

print(current_date)  # Output: Current date

current_time = datetime.time()

print(current_time)  # Output: Current time

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