String manipulation

Invert the case of each alphabetic character in a string.

Preparing user input for case‑insensitive matching; creating a simple visual effect by flipping case; generating a transformed version of a string for testing case‑sensitive code.

Any Python program that works with strings; standard library scripts, data cleaning, UI text generation.

; .swapcase()

; .swapcase()

string_expression: any expression that evaluates to a string (variable, literal, or function call).

• str.upper()
• str.lower()
• str.title()
• str.strip()

• Using a comprehension: ''.join(c.lower() if c.isupper() else c.upper() for c in s)
• or str.translate with a custom translation table.

Assuming the method modifies the original string (strings are immutable); applying it to non‑string objects without conversion; expecting it to affect non‑alphabetic characters.

str.upper() (makes all characters uppercase); str.lower() (makes all lowercase); str.capitalize() (capitalizes first character only).

Coming from languages with mutable character arrays (e.g., C): may expect in‑place modification; remember that Python strings are immutable and swapcase() returns a new string.

• string case conversion methods
• string transformation methods

The transformation follows Unicode case mapping rules and is locale‑independent; symbols, digits, and punctuation remain unchanged; the result length equals the input length.

Provides a quick, readable way to invert case without explicit loops or conditionals.

Think of 'swap' as swapping hats: uppercase ↔ lowercase.

swapcase() returns a new string; the original string remains unchanged.

For more complex case transformations, use str.translate() with a custom translation table or regular expressions with re.sub() and a lambda.