Linear time complexity describes work that grows with the number of elements processed. Searching a string, list, or tuple one element at a time takes O(n): longer sequences require proportionally more searching. section 4.1
Python’s in operator provides a readable way to perform this kind of search. It effectively examines sequence elements in turn, making linear time a practical choice for many short strings and collections. section 2.3
Checking for a vowel
Instead of repeating comparisons for every vowel, use `if word[0] in 'aeiou':`. The concise form preserves the linear-search behavior while improving readability. section 2.3
if word[0] in 'aeiou':
Compare the idiomatic membership test with longer repeated-condition and explicit-loop alternatives. section 2.3
