Lesson 9: String methods

Strings have built-in methods that return a new, processed string: .upper() and .lower() change letter case, .strip() removes whitespace from the start and end, and .replace() swaps text. Important: the original string is not changed — you get a new string back.

String methods are like filters: a string goes in and a processed copy comes out. The original stays as it was.

string method: An action called on a string with a dot, e.g. s.upper(), returning a new string.
.strip(): Removes whitespace from the start and end of the string.
.replace(): Returns a new string where every occurrence of one text is replaced by another.