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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 785 · 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 = ["Zoya", "Kabir", "Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Aman (b) Hi, Meera (c) Hi, Kabir (d) Hi, Zoya
  2. 2.🔁 What number does this code show?
    let steps = [17, 11, 6, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  3. 3.🔁 What number does this code show?
    let runs = [30, 23, 21, 64, 64];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  4. 4.🔁 What does a loop do? (a) saves photos (b) deletes code (c) repeats code (d) draws icons
  5. 5.🔁 What number does this code show?
    let scores = [16, 8, 17];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  6. 6.🔁 What number does this code show?
    let scores = [11, 6, 9];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  7. 7.🔁 What number does this code show?
    let marks = [82, 10, 22];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  8. 8.🔁 What number does this code show?
    let steps = [19, 15, 11];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  9. 9.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Aman
  10. 10.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2 (c) 3 (d) 0, 1, 2, 3
  11. 11.🔁 What number does this code show?
    let steps = [70, 35, 10, 50, 30];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Arjun (c) Hi, Kabir
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya
  14. 14.🔁 What number does this code show?
    let steps = [41, 53, 11];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  15. 15.🔁 What number does this code show?
    let runs = [4, 9, 19];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  16. 16.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Riya (d) Hi, Kabir
  17. 17.🔁 What number does this code show?
    let steps = [4, 8, 12, 20];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  18. 18.🔁 What number does this code show?
    let runs = [14, 9, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Kabir (b) Hi, Riya (c) Hi, Meera
  20. 20.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Riya (c) Hi, Zoya
  21. 21.🔁 What number does this code show?
    let scores = [3, 3, 6, 18, 4];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  22. 22.🔁 What number does this code show?
    let scores = [14, 19, 2, 6, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  23. 23.🔁 What number does this code show?
    let steps = [19, 13, 16];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let runs = [10, 18, 8, 10, 17];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  25. 25.🔁 What number does this code show?
    let marks = [21, 50, 94, 95, 93];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What number does this code show?
    let steps = [10, 5, 17, 17, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  27. 27.🔁 What number does this code show?
    let marks = [5, 13, 6, 14, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  28. 28.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya (d) Hi, Meera
  29. 29.🔁 What number does this code show?
    let runs = [34, 49, 68, 92];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What number does this code show?
    let runs = [9, 17, 4, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  31. 31.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Aman (c) Hi, Kabir
  32. 32.🔁 What number does this code show?
    let scores = [5, 3, 8, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  33. 33.🔁 What number does this code show?
    let scores = [10, 14, 1, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  34. 34.🔁 What number does this code show?
    let scores = [10, 11, 4, 16, 20];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  35. 35.🔁 What number does this code show?
    let runs = [98, 39, 47, 74];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let scores = [12, 13, 9];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  37. 37.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 1 (d) 5
  38. 38.🔁 What number does this code show?
    let marks = [13, 16, 2];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  39. 39.🔁 What number does this code show?
    let scores = [16, 5, 12, 18];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  40. 40.🔁 What number does this code show?
    let scores = [4, 4, 19, 5, 20];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

Answer key

  1. Hi, Aman
  2. 17
  3. 2
  4. repeats code
  5. 17
  6. 11
  7. 1
  8. 19
  9. Hi, Aman
  10. 0, 1, 2
  11. 2
  12. Hi, Arjun
  13. Hi, Aman
  14. 0
  15. 32
  16. Hi, Arjun
  17. 44
  18. 39
  19. Hi, Meera
  20. Hi, Riya
  21. 18
  22. 61
  23. 19
  24. 18
  25. 3
  26. 52
  27. 55
  28. Hi, Meera
  29. 2
  30. 34
  31. Hi, Arjun
  32. 26
  33. 14
  34. 20
  35. 2
  36. 34
  37. 5
  38. 31
  39. 18
  40. 20

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