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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 863 · 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 does a loop do? (a) deletes code (b) saves photos (c) repeats code (d) draws icons
  2. 2.🔁 What number does this code show?
    let runs = [13, 3, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  3. 3.🔁 What number does this code show?
    let runs = [13, 7, 1, 14];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  4. 4.🔁 What number does this code show?
    let scores = [9, 8, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  5. 5.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Arjun", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Riya
  6. 6.🔁 What number does this code show?
    let steps = [14, 14, 15, 14, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  7. 7.🔁 What number does this code show?
    let runs = [10, 8, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  8. 8.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Zoya", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Meera (d) Hi, Riya
  9. 9.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Aman (c) Hi, Arjun (d) Hi, Zoya
  10. 10.🔁 What number does this code show?
    let marks = [4, 1, 4, 7, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  11. 11.🔁 What number does this code show?
    let runs = [30, 44, 15];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) how many items it has (d) the first item
  13. 13.🔁 What number does this code show?
    let runs = [3, 17, 5, 13, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  14. 14.🔁 What number does this code show?
    let runs = [16, 4, 12];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  15. 15.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Meera
  16. 16.🔁 What number does this code show?
    let marks = [18, 15, 9];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  17. 17.🔁 What number does this code show?
    let steps = [87, 51, 84];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What number does this code show?
    let scores = [60, 60, 97, 81];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  19. 19.🔁 What number does this code show?
    let marks = [2, 11, 2, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  20. 20.🔁 What number does this code show?
    let marks = [2, 3, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  21. 21.🔁 What number does this code show?
    let steps = [14, 1, 2, 17];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  22. 22.🔁 What number does this code show?
    let runs = [71, 71, 60];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  23. 23.🔁 What number does this code show?
    let scores = [1, 9, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let scores = [19, 5, 2, 4, 13];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  25. 25.🔁 What number does this code show?
    let steps = [14, 33, 13, 63, 54];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 6 (c) 1 (d) 4
  27. 27.🔁 What number does this code show?
    let steps = [27, 83, 92, 51];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Aman", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman (d) Hi, Meera
  29. 29.🔁 What number does this code show?
    let steps = [20, 6, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  30. 30.🔁 What number does this code show?
    let scores = [47, 14, 51, 82];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let runs = [3, 3, 17, 8, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  32. 32.🔁 What number does this code show?
    let runs = [87, 57, 60, 82];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What number does this code show?
    let steps = [19, 12, 13];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  34. 34.🔁 What number does this code show?
    let runs = [7, 14, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  35. 35.🔁 What number does this code show?
    let steps = [57, 22, 24];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let steps = [1, 11, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  37. 37.🔁 What number does this code show?
    let runs = [19, 15, 12, 7, 20];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  38. 38.🔁 What number does this code show?
    let scores = [69, 50, 12, 11, 69];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  39. 39.🔁 What number does this code show?
    let marks = [13, 7, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let steps = [11, 7, 14, 17, 17];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);

Answer key

  1. repeats code
  2. 25
  3. 14
  4. 32
  5. Hi, Zoya
  6. 15
  7. 20
  8. Hi, Riya
  9. Hi, Arjun
  10. 30
  11. 1
  12. how many items it has
  13. 39
  14. 16
  15. Hi, Meera
  16. 42
  17. 3
  18. 4
  19. 35
  20. 13
  21. 34
  22. 2
  23. 9
  24. 43
  25. 0
  26. 5
  27. 2
  28. Hi, Arjun
  29. 38
  30. 1
  31. 17
  32. 2
  33. 44
  34. 33
  35. 1
  36. 11
  37. 20
  38. 0
  39. 37
  40. 66

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