Chapter Review Questions

Note

Source: Questions 1–5 adapted from the C# edition (basicstringops/reviewstring.rst). Questions 6–10 are original additions specific to Python.

1. What is printed by this fragment?

   s = "question"
   print(len(s))
   print(s[2])
   print(s[2:5])
   print(s[3:])
   print(s.find("ti"))
   print(s.find("to"))
   

2. What is printed by this fragment?

   s = "Word"
   s.upper()
   print(s)
   

3. What is printed by this fragment?

   a = "hi"
   b = a.upper()
   print(a + b)
   

4. Strings and mutability.

   1. Are strings mutable or immutable?

   2. What does that mean in practice when you call a method like s.upper()?

5. Both s.find(sub) and s.index(sub) search for a substring. What is the difference in their behavior when the substring is not present in s?

6. Write an expression that extracts the last three characters of a string s, without using a literal index number.

7. What does s[::-1] do?

8. Write a function count_vowels(s) that returns the number of vowel characters (a, e, i, o, u, case-insensitive) in string s.

9. What is printed by this fragment?

   parts = "2024-05-01".split("-")
   print(parts)
   print("-".join(parts))
   

10. Write a function title_case(s) that returns s converted to title case (first letter of each word capitalized) without using the built-in str.title() method. Use split() and join().