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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 865 · 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 number does this code show?
    let marks = [7, 15, 1, 11];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  2. 2.🔁 What number does this code show?
    let steps = [77, 83, 86, 21];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  3. 3.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Zoya (d) Hi, Aman
  4. 4.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Aman (c) Hi, Meera
  5. 5.🔁 What number does this code show?
    let scores = [11, 17, 3, 14, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  6. 6.🔁 What number does this code show?
    let steps = [50, 90, 30, 52];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  7. 7.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2 (c) 1, 2, 3 (d) 0, 1, 2, 3
  8. 8.🔁 What number does this code show?
    let scores = [20, 9, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  9. 9.🔁 What number does this code show?
    let marks = [3, 3, 15];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  10. 10.🔁 What number does this code show?
    let steps = [2, 11, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  11. 11.🔁 What number does this code show?
    let scores = [9, 7, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  12. 12.🔁 What number does this code show?
    let steps = [17, 29, 90];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What number does this code show?
    let scores = [9, 9, 7, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  14. 14.🔁 What does a loop do? (a) draws icons (b) saves photos (c) deletes code (d) repeats code
  15. 15.🔁 What number does this code show?
    let scores = [11, 28, 83, 58, 80];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 What number does this code show?
    let scores = [17, 10, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  17. 17.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Meera (c) Hi, Aman (d) Hi, Zoya
  18. 18.🔁 What number does this code show?
    let steps = [65, 74, 72];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  19. 19.🔁 What number does this code show?
    let scores = [79, 14, 47];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  20. 20.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 4 (d) 5
  21. 21.🔁 What number does this code show?
    let marks = [12, 15, 11];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  22. 22.🔁 What number does this code show?
    let marks = [13, 1, 17];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  23. 23.🔁 What number does this code show?
    let runs = [1, 8, 13, 9, 2];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let marks = [7, 14, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  25. 25.🔁 What number does this code show?
    let runs = [4, 4, 17, 1, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman
  27. 27.🔁 What number does this code show?
    let steps = [99, 76, 71];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 list.length tells you ___. (a) how many items it has (b) the last item (c) the first item (d) the biggest item
  29. 29.🔁 What number does this code show?
    let runs = [3, 18, 6, 5, 7];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  30. 30.🔁 What number does this code show?
    let runs = [40, 84, 39];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Riya
  32. 32.🔁 What number does this code show?
    let runs = [6, 13, 9, 9, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  33. 33.🔁 What number does this code show?
    let scores = [97, 39, 10];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  34. 34.🔁 What number does this code show?
    let runs = [43, 23, 19, 13];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  35. 35.🔁 What number does this code show?
    let scores = [20, 17, 18, 16, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  36. 36.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya
  37. 37.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya (d) Hi, Aman
  38. 38.🔁 What number does this code show?
    let steps = [20, 5, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  39. 39.🔁 What number does this code show?
    let marks = [10, 37, 25];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  40. 40.🔁 What number does this code show?
    let marks = [12, 95, 37, 85, 16];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. 15
  2. 3
  3. Hi, Meera
  4. Hi, Arjun
  5. 46
  6. 3
  7. 0, 1, 2
  8. 35
  9. 21
  10. 18
  11. 24
  12. 1
  13. 9
  14. repeats code
  15. 2
  16. 39
  17. Hi, Kabir
  18. 2
  19. 1
  20. 5
  21. 38
  22. 17
  23. 13
  24. 14
  25. 32
  26. Hi, Arjun
  27. 3
  28. how many items it has
  29. 39
  30. 1
  31. Hi, Zoya
  32. 16
  33. 1
  34. 0
  35. 79
  36. Hi, Aman
  37. Hi, Arjun
  38. 20
  39. 0
  40. 2

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