Modifying Strings0%
Concatenation & Formatting (f-string, format, %)

Modifying Strings

Beginner8 min read•Updated: 2026-09-03
Study Materials

Modifying Strings

String methods transform text and return brand-new string objects.

Key Concepts & Detailed Explanation

Common modification methods:

  • .upper() / .lower(): Convert entirely to uppercase / lowercase.
  • .strip(): Strip leading and trailing whitespace.
  • .replace(old, new): Replace substring occurrences.
  • .title(): Capitalize the first letter of each word.
  • .capitalize(): Capitalize the first letter of the entire string.

Code Examples & Output

Python
raw_text = " python programming masterclass "
 
print("Upper:", raw_text.strip().upper())
print("Title:", raw_text.strip().title())
print("Replaced:", raw_text.replace("masterclass", "bootcamp").strip())

Expected Output:

Output
Upper: PYTHON PROGRAMMING MASTERCLASS
Title: Python Programming Masterclass
Replaced: python programming bootcamp

Best Practices & Common Pitfalls

Always call .strip() on user input before validating or storing in a database.

Practice Quiz

1. Which method eliminates whitespace from both ends of a string?

  • A) trim()
  • B) strip()
  • C) clean()
  • D) cut()
Answer: B Explanation: strip() removes whitespace from both ends.

2. What does 'hello world'.title() produce?

  • A) Hello world
  • B) HELLO WORLD
  • C) Hello World
  • D) hello World
Answer: C Explanation: title() capitalizes each word, producing 'Hello World'.

Practice Challenge

Clean up a messy input ' jOhN dOE ' to display 'John Doe'.

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