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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 620 · 40 questions
TalentJR

Developer's tip (One by one): for (let i = 0; i < list.length; i++) visits every item, from position 0. Total: add each item. Count: add 1 when the test is true. Best: keep the biggest so far. The body runs once per item: a list of 5 runs it 5 times.

NameDateTime takenScore ___ / 40
  1. 1.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Riya (c) Hi, Aman
  2. 2.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) how many items it has (d) the first item
  3. 3.🔁 What number does this code show?
    let scores = [7, 6, 9, 8];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  4. 4.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman
  5. 5.🔁 What number does this code show?
    let marks = [29, 46, 12, 22];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Aman
  7. 7.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 1 (c) 6 (d) 4
  8. 8.🔁 What does a loop do? (a) deletes code (b) repeats code (c) draws icons (d) saves photos
  9. 9.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Arjun
  10. 10.🔁 What number does this code show?
    let runs = [1, 11, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  11. 11.🔁 What number does this code show?
    let runs = [15, 12, 22, 34];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 3 (d) 0, 1, 2
  13. 13.🔁 What number does this code show?
    let steps = [3, 16, 19, 16];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  14. 14.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it is slower (c) it uses more lines (d) it hides them
  15. 15.🔁 What number does this code show?
    let marks = [23, 17, 51, 11, 21];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 What number does this code show?
    let scores = [86, 38, 54, 85, 90];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Arjun", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya
  18. 18.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Kabir
  19. 19.🔁 What number does this code show?
    let scores = [18, 9, 13, 12];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  20. 20.🔁 What number does this code show?
    let scores = [10, 12, 18];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  21. 21.🔁 What number does this code show?
    let scores = [5, 8, 5, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  22. 22.🔁 What number does this code show?
    let runs = [15, 12, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  23. 23.🔁 What number does this code show?
    let marks = [19, 18, 2, 4, 2];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  24. 24.🔁 What number does this code show?
    let marks = [94, 63, 21];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  25. 25.🔁 What number does this code show?
    let scores = [16, 14, 17, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  26. 26.🔁 What number does this code show?
    let runs = [17, 10, 17, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  27. 27.🔁 What number does this code show?
    let runs = [5, 7, 6, 13];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  28. 28.🔁 What number does this code show?
    let scores = [8, 20, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  29. 29.🔁 What number does this code show?
    let runs = [86, 86, 58];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What number does this code show?
    let runs = [56, 31, 19, 90];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let scores = [14, 87, 34, 82];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  32. 32.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Riya (c) Hi, Meera (d) Hi, Arjun
  33. 33.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Aman (d) Hi, Riya
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun
  35. 35.🔁 What number does this code show?
    let steps = [11, 62, 54, 22];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let scores = [10, 9, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  37. 37.🔁 What number does this code show?
    let scores = [1, 6, 13, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  38. 38.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Kabir (c) Hi, Meera
  39. 39.🔁 What number does this code show?
    let steps = [11, 11, 2, 7, 12];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  40. 40.🔁 What number does this code show?
    let steps = [31, 73, 38];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. Hi, Kabir
  2. how many items it has
  3. 9
  4. Hi, Meera
  5. 0
  6. Hi, Riya
  7. 5
  8. repeats code
  9. Hi, Riya
  10. 25
  11. 0
  12. 0, 1, 2
  13. 19
  14. less code to write
  15. 1
  16. 3
  17. Hi, Riya
  18. Hi, Zoya
  19. 18
  20. 18
  21. 25
  22. 43
  23. 45
  24. 2
  25. 52
  26. 46
  27. 13
  28. 38
  29. 2
  30. 1
  31. 2
  32. Hi, Riya
  33. Hi, Aman
  34. Hi, Meera
  35. 0
  36. 25
  37. 13
  38. Hi, Meera
  39. 12
  40. 1

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