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Python BasicsPython Basics11
❯

  1. 1Introduction to Python
  2. 2Python Hello World Program
  3. 3Python Comments Explained - Beginner’s Guide with Examples
  4. 4Python Variables
  5. 5Python Constants
  6. 6Python Data Types
  7. 7Python Strings
  8. 8Python Type Conversions
  9. 9Python Basic Input and Output - Learn to Take User Input and Print Output
  10. 10Python Operators
  11. 11Python Operator Precedence – Evaluation Order with Examples

Python Flow ControlPython Flow Control5
❯

  1. 1Python Conditional Statements
  2. 2Python Loops
  3. 3Python For Loop
  4. 4Python While Loop
  5. 5Python Break and Continue

Python CollectionsPython Collections5
❯

  1. 1Introduction to Python Collections
  2. 2Python Lists
  3. 3Python Dictionaries
  4. 4Python Tuples
  5. 5Python Sets

Python FunctionsPython Functions4
❯

  1. 1Python Functions
  2. 2Python Functions with Parameters
  3. 3Python main() Function
  4. 4Python Lambda Functions

Python File HandlingPython File Handling1
❯

  1. 1Python File Operations – Read, Write, Update & Delete Files

Python Exception HandlingPython Exception Handling3
❯

  1. 1What Are Python Exceptions?
  2. 2Python Exception Handling
  3. 3Python Custom Exceptions

Python OOPsPython OOPs5
❯

  1. 1Python Object-Oriented Programming
  2. 2Python Inheritance
  3. 3Python Multiple Inheritance
  4. 4Python Encapsulation
  5. 5Python Polymorphism

Python Advanced ConceptsPython Advanced Concepts5
❯

  1. 1Python List Comprehension
  2. 2Python Iterators
  3. 3Python Generators
  4. 4Python Closures
  5. 5Python Decorators

Python LibrariesPython Libraries3
❯

  1. 1Python Email Tutorial
  2. 2Python JSON Tutorial – Parse, Read, Write & Handle JSON in Python
  3. 3Python datetime Tutorial - Working with Dates and Times in Python

Python ReferencePython Reference2
❯

  1. 1Python Built-in Functions
  2. 3Python String Methods

Python Built-in FunctionsPython Built-in Functions0
❯

    Python String MethodsPython String Methods0
    ❯

      ProgramGuru

      Python String lower() Method – Convert to Lowercase

      Python String lower() Method

      The lower() method in Python is used to convert all the characters in a string to lowercase. It's useful when comparing strings or working with user input where case sensitivity doesn't matter.

      Syntax

      string.lower()

      Parameters:

      • None – This method does not take any arguments.

      Returns:

      • A new string where all uppercase characters are converted to lowercase.

      Example 1: Basic Usage

      text = "HELLO WORLD"
print(text.lower())
      hello world

      Example 2: Mixed Case String

      greeting = "GoOd MoRnInG"
print(greeting.lower())
      good morning

      Why Use lower()?

      • To make string comparison case-insensitive.
      • To clean up user input before storing or validating.
      • To normalize data for searching or sorting.

      Example 3: Comparing Strings

      a = "Python"
b = "PYTHON"
print(a.lower() == b.lower())
      True

      Even though the original strings differ in case, they are equal after using lower().

      Does lower() Change the Original String?

      No, strings in Python are immutable. The lower() method returns a new string — it doesn’t modify the original one.

      Common Mistake

      name = "ALICE"
name.lower()
print(name)
      ALICE

      Why? Because name.lower() returns a new string, but it wasn't assigned back to name.

      Correct Way:

      name = name.lower()
print(name)

      Summary

      • lower() converts a string to lowercase.
      • Returns a new string — original is not changed.
      • Helps with case-insensitive comparisons and text cleaning.

      Practice Problem

      Ask the user to input a sentence and print it in lowercase.

      text = input("Enter a sentence: ")
print("In lowercase:", text.lower())

      Python String Methods❯

      1. 1Python String capitalize() – Capitalize First Letter of a String
      2. 2Python String casefold() – Case-Insensitive String Comparison
      3. 3Python String center() Method – Center Align a String with Padding
      4. 4Python String count() Method – Count Substring Occurrences
      5. 5Python string.encode() – Convert String to Bytes
      6. 6Python String endswith() – Check if a String Ends with Substring
      7. 7Python String expandtabs() – Replace Tabs with Spaces
      8. 8Python String find() – How to Locate Substrings Easily
      9. 9Python String index() Method – Find Position of a Substring
      10. 10Python String isalnum() Method – Check Alphanumeric Strings
      11. 11Python String isalpha() Method – Check for Alphabetic Characters
      12. 12Python String isascii() Method – Check for ASCII Characters
      13. 13Python String isdecimal() Method – Check if All Characters Are Decimals
      14. 14Python String isdigit() Method – Check If a String Has Only Digits
      15. 15Python String isidentifier() – Check for Valid Identifiers
      16. 16Python String islower() Method – Check for Lowercase Strings
      17. 17Python String isnumeric() Method – Check for Numeric Characters
      18. 18Python String isprintable() Method – Check Printable Characters
      19. 19Python String isspace() Method – Check for Whitespace Only
      20. 20Python String istitle() Method – Check for Title Case
      21. 21Python String isupper() Method – Check for Uppercase Letters
      22. 22Python String join() Method – Combine Strings Easily
      23. 23Python String ljust() Method – Left Justify a String with Spaces or Characters
      24. 24Python String lower() Method – Convert to Lowercase
      25. 25Python String lstrip() Method – Remove Leading Characters
      26. 26Python String maketrans() Method – Create Translation Tables
      27. 27Python String partition() Method – Split into Three Parts
      28. 28Python String replace() Method – Replace Substrings Easily
      29. 29Python String rfind() Method – Find Last Occurrence of Substring
      30. 30Python String rindex() Method – Find Last Occurrence of a Substring
      31. 31Python String rjust() Method – Right Justify a String
      32. 32Python String rpartition() Method – Split String from the Right
      33. 33Python String rsplit() Method – Split from the Right
      34. 34Python String rstrip() Method – Remove Trailing Characters
      35. 35Python String split() Method – Split Strings Easily
      36. 36Python String splitlines() Method – Split String by Line Breaks
      37. 37Python String startswith() Method – Check If a String Starts With
      38. 38Python String strip() Method – Remove Spaces from Ends
      39. 39Python String swapcase() Method – Convert Uppercase to Lowercase and Vice Versa
      40. 40Python String title() Method – Convert to Title Case
      41. 41Python String translate() Method – Replace Characters Using Mapping
      42. 42Python String upper() Method – Convert to Uppercase
      43. 43Python String zfill() Method – Pad String with Zeros

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