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Quiz: String Methods and Formatting

Test your understanding of string indexing, slicing, methods, and f-strings with these questions. Click "Show Answer" to reveal the correct answer and explanation.

1. What index does the first character of a Python string have?

  1. 1
  2. -1
  3. 0
  4. The index depends on the length of the string
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The correct answer is C. Python strings (and most Python sequences) use zero-based indexing — the first character is at index 0, the second at 1, and so on. So for the string "Python", word[0] gives "P", word[1] gives "y", and word[5] gives "n".

Concept Tested: String Indexing

2. What does "Python"[-1] return?

  1. "P" (the first character)
  2. An error, because negative indexes are not allowed
  3. "n" (the last character)
  4. 6 (the length of the string)
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The correct answer is C. Negative indexes count backwards from the end of the string. Index -1 is the last character, -2 is second-to-last, and so on. For "Python", index -1 is "n". This is convenient when you want the last character without knowing the string's length.

Concept Tested: String Indexing

3. What does "programming"[0:4] return?

  1. "prog"
  2. "rogr"
  3. "prog " (with a space)
  4. "rogramming"
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The correct answer is A. String slicing [start:end] returns characters from index start up to, but NOT including, index end. "programming"[0:4] gives characters at indexes 0, 1, 2, and 3 — which are p, r, o, g — forming "prog". The character at index 4 (a) is not included.

Concept Tested: String Slicing

4. What does "hello world".split() return?

  1. "hello" and "world" as two separate print statements
  2. ["hello", "world"] — a list of two strings
  3. "hello,world" with a comma added
  4. 11 — the number of characters including the space
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The correct answer is B. split() with no argument breaks a string at every whitespace and returns a list of the pieces. "hello world".split() returns the list ["hello", "world"]. You can also split on a specific character: "a,b,c".split(",") returns ["a", "b", "c"].

Concept Tested: split() Method

5. What does "-".join(["a", "b", "c"]) return?

  1. "a-b-c"
  2. ["a", "b", "c"] unchanged
  3. "-a-b-c-"
  4. "abc" with no separator
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The correct answer is A. join() glues a list of strings together using the string it is called on as the separator. "-".join(["a", "b", "c"]) returns "a-b-c". The separator appears between items but not at the beginning or end. join() is the reverse of split().

Concept Tested: join() Method

6. What does "the fox ran".replace("fox", "dog") return?

  1. "the fox ran" unchanged
  2. "the dog ran"
  3. "the dog dog ran" replacing once
  4. An error, because replace() requires three arguments
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The correct answer is B. replace(old, new) returns a new string with every occurrence of old replaced by new. "the fox ran".replace("fox", "dog") returns "the dog ran". Note that strings are immutable — replace() does not change the original string; it returns a new one.

Concept Tested: replace() Method

7. What does "report.pdf".endswith(".pdf") return?

  1. The index where ".pdf" starts in the string
  2. True
  3. False
  4. ".pdf" (the matching suffix)
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The correct answer is B. endswith(suffix) returns True if the string ends with the given suffix, False otherwise. "report.pdf".endswith(".pdf") returns True because the string does end with ".pdf". This is very useful for checking file extensions, URL endings, and other suffix patterns.

Concept Tested: String Search Methods

8. What is an f-string in Python?

  1. A string that can only hold floating-point numbers
  2. A special "fast" string type that runs faster than regular strings
  3. A formatted string literal that lets you embed variables directly using {variable} inside the string
  4. A string defined with triple quotes for multiple lines
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The correct answer is C. An f-string (formatted string literal) is created by putting f before the opening quote: f"Hello, {name}!". Any expression inside {} is evaluated and inserted into the string. F-strings replace the need to convert numbers with str() before joining and are much more readable than concatenation.

Concept Tested: f-Strings

9. What does f"Score: {95:.1f}%" produce?

  1. "Score: 95%"
  2. "Score: 95.0%"
  3. "Score: 95.1%"
  4. An error because integers cannot use .1f format
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The correct answer is B. The format spec :.1f inside an f-string formats a number as a float with exactly 1 decimal place. 95 formatted as :.1f becomes 95.0. So f"Score: {95:.1f}%" produces "Score: 95.0%". Format specs like .2f (2 decimal places) or .0f (no decimals) give you precise control over numeric display.

Concept Tested: f-Strings

10. What does s.find("xyz") return when "xyz" is not found in the string s?

  1. None
  2. False
  3. An error is raised
  4. -1
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The correct answer is D. find() returns the index of the first occurrence of the search string. If the search string is not found, find() returns -1 rather than raising an error. This lets you check the result: if s.find("xyz") != -1: means "if xyz was found." The in operator ("xyz" in s) is another common way to check without worrying about the index.

Concept Tested: String Search Methods