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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 270 · 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", "Kabir", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman (d) Hi, Kabir
  2. 2.🔁 What number does this code show?
    let runs = [2, 14, 12, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  3. 3.🔁 What number does this code show?
    let steps = [14, 6, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  4. 4.🔁 What number does this code show?
    let steps = [3, 5, 10, 3, 4];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  5. 5.🔁 What number does this code show?
    let runs = [9, 11, 10, 12, 9];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  6. 6.🔁 What number does this code show?
    let steps = [3, 20, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  7. 7.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Arjun (d) Hi, Kabir
  8. 8.🔁 What number does this code show?
    let marks = [11, 3, 20, 18, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  9. 9.🔁 What number does this code show?
    let marks = [13, 18, 6, 15, 3];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  10. 10.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 6 (c) 1 (d) 4
  11. 11.🔁 What number does this code show?
    let runs = [76, 91, 27, 47, 10];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 What number does this code show?
    let scores = [18, 12, 14, 1, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Kabir
  14. 14.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman
  15. 15.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Meera
  16. 16.🔁 What number does this code show?
    let scores = [12, 14, 18, 6, 4];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  17. 17.🔁 What number does this code show?
    let steps = [75, 61, 14, 53, 37];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What number does this code show?
    let steps = [2, 20, 10];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Riya
  20. 20.🔁 What number does this code show?
    let runs = [48, 36, 32];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun (d) Hi, Aman
  22. 22.🔁 What number does this code show?
    let scores = [8, 12, 6, 9];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  23. 23.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 0, 1, 2, 3 (c) 3 (d) 1, 2, 3
  24. 24.🔁 What number does this code show?
    let steps = [98, 11, 69];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  25. 25.🔁 What number does this code show?
    let runs = [3, 19, 5, 6, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  26. 26.🔁 What number does this code show?
    let scores = [6, 5, 16, 4, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  27. 27.🔁 What does a loop do? (a) saves photos (b) deletes code (c) repeats code (d) draws icons
  28. 28.🔁 What number does this code show?
    let marks = [2, 16, 16, 4];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  29. 29.🔁 list.length tells you ___. (a) the last item (b) the first item (c) the biggest item (d) how many items it has
  30. 30.🔁 What number does this code show?
    let runs = [77, 31, 91];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let scores = [15, 2, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  32. 32.🔁 What number does this code show?
    let runs = [16, 81, 23];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Riya (c) Hi, Arjun (d) Hi, Zoya
  34. 34.🔁 What number does this code show?
    let steps = [8, 12, 17, 10];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  35. 35.🔁 What number does this code show?
    let steps = [16, 1, 9, 18, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  36. 36.🔁 What number does this code show?
    let steps = [6, 13, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  37. 37.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Kabir", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Aman (d) Hi, Arjun
  38. 38.🔁 What number does this code show?
    let scores = [4, 13, 8, 1, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  39. 39.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Aman
  40. 40.🔁 What number does this code show?
    let steps = [20, 3, 8, 4, 8];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);

Answer key

  1. Hi, Aman
  2. 14
  3. 14
  4. 10
  5. 12
  6. 20
  7. Hi, Zoya
  8. 20
  9. 55
  10. 5
  11. 2
  12. 46
  13. Hi, Aman
  14. Hi, Arjun
  15. Hi, Riya
  16. 18
  17. 2
  18. 20
  19. Hi, Kabir
  20. 0
  21. Hi, Aman
  22. 35
  23. 0, 1, 2
  24. 1
  25. 39
  26. 41
  27. repeats code
  28. 38
  29. how many items it has
  30. 2
  31. 31
  32. 1
  33. Hi, Kabir
  34. 47
  35. 18
  36. 13
  37. Hi, Zoya
  38. 31
  39. Hi, Kabir
  40. 20

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