Data Analysis with Python Zero to Pandas

Introduction

• Free certification course at zerotopandas.com
• Instructor: Aakash
• Focus: Basics of Python

Lesson 2: Conditional Statements and Loops

Conditional Statements

• Branching: Decision making in code execution based on conditions.
• If Statement:
  • Syntax: if condition: followed by indented block.
  • Example: Check if a number is even using modulus operator.
• Else Statement:
  • Execute alternate block when condition is false.
  • Example: Print whether number is odd or even.
• Elif Statement:
  • Check multiple conditions in sequence.
  • Example: Print messages based on the day of the week.
• Truth Values:
  • Non-boolean values can be conditions; empty values = false, others = true.
• Nesting:
  • If statements can be nested but avoid deep nesting for clarity.

Loops

• While Loop:

  • Executes block repeatedly while condition is true.
  • Example: Calculate factorial of a number using a loop.
  • Infinite Loops: Occurs if condition never becomes false. Use Kernel Interrupt or stop button.
  • Break Statement: Exit loop before condition is false.
  • Continue Statement: Skip rest of loop block, continue with next iteration.

• For Loop:

  • Iterate over a sequence (list, string, dictionary).
  • Syntax: for value in sequence:
  • Range Function: Define a sequence of numbers for iteration.
  • Example: Loop through days of the week or iterate over dictionary items.
  • Break and Continue: Similar usage as in while loop.

Functions and Scope

• Defining Functions:

  • Use def keyword, can take inputs (arguments), return outputs.
  • Example Function: say_hello prints a message.

• Arguments and Parameters:

  • Functions can accept multiple arguments, making them flexible.
  • Example: filter_even filters even numbers from a list.

• Scope:

  • Variables inside functions are local (not accessible outside).

• Advanced Function Features:

  • Return Values: Use return to provide output from function.
  • Default Arguments: Specify a default value for function parameters.
  • Named Arguments: Specify parameter names during function call for clarity.

• Modules: Import external Python files, use functions without polluting namespace.

  • Example: import math to use math.ceil

Error Handling

• Try-Except Block:
  • Catch and handle exceptions, such as divide by zero errors.
  • Example: Handle zero division error in EMI calculation.

Documentation

• Docstrings: Document functions with descriptions.
  • Use help function to view docstring.

Exercises and Further Practice

• Practice exercises provided to reinforce learning.
• Encourage participation in forums for questions and discussion.