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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 985 · 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 scores = [46, 12, 76, 80, 39];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  2. 2.🔁 What number does this code show?
    let runs = [15, 14, 19, 3, 20];
    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 scores = [1, 3, 3, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  4. 4.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
  5. 5.🔁 What number does this code show?
    let scores = [14, 67, 95];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the first item (d) the biggest item
  7. 7.🔁 What number does this code show?
    let steps = [10, 8, 5, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  8. 8.🔁 What number does this code show?
    let marks = [19, 19, 6, 17, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  9. 9.🔁 What number does this code show?
    let runs = [3, 9, 4, 4, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  10. 10.🔁 What number does this code show?
    let runs = [13, 1, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  11. 11.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir (d) Hi, Aman
  12. 12.🔁 What number does this code show?
    let runs = [3, 9, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  13. 13.🔁 What number does this code show?
    let steps = [9, 1, 6, 13, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  14. 14.🔁 What number does this code show?
    let scores = [96, 80, 80];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  15. 15.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Aman", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Arjun
  16. 16.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Meera", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Aman (c) Hi, Riya (d) Hi, Meera
  17. 17.🔁 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
  18. 18.🔁 What number does this code show?
    let marks = [17, 11, 10];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  19. 19.🔁 What number does this code show?
    let scores = [24, 14, 20];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  20. 20.🔁 What number does this code show?
    let steps = [19, 99, 89];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What number does this code show?
    let scores = [17, 13, 20, 16, 5];
    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 = [16, 13, 2, 15, 19];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  23. 23.🔁 What number does this code show?
    let marks = [51, 14, 31, 16, 79];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  24. 24.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
  25. 25.🔁 What number does this code show?
    let scores = [2, 19, 8, 4, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  26. 26.🔁 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, Kabir (b) Hi, Zoya (c) Hi, Aman
  27. 27.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Riya (c) Hi, Aman (d) Hi, Kabir
  28. 28.🔁 What number does this code show?
    let runs = [53, 17, 24];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Arjun
  30. 30.🔁 What number does this code show?
    let marks = [15, 48, 28, 10, 93];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What does a loop do? (a) deletes code (b) saves photos (c) repeats code (d) draws icons
  32. 32.🔁 What number does this code show?
    let marks = [16, 4, 4, 13, 13];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  33. 33.🔁 What number does this code show?
    let steps = [7, 3, 11, 10, 16];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  34. 34.🔁 What number does this code show?
    let steps = [13, 4, 8];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  35. 35.🔁 What number does this code show?
    let scores = [88, 92, 89];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let runs = [9, 14, 14];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  37. 37.🔁 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, Aman (c) Hi, Kabir
  38. 38.🔁 What number does this code show?
    let marks = [61, 20, 51, 49];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  39. 39.🔁 What number does this code show?
    let scores = [11, 13, 12, 10, 3];
    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 = [6, 18, 5, 20, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);

Answer key

  1. 3
  2. 20
  3. 25
  4. 5
  5. 2
  6. how many items it has
  7. 10
  8. 75
  9. 30
  10. 27
  11. Hi, Arjun
  12. 21
  13. 18
  14. 3
  15. Hi, Arjun
  16. Hi, Kabir
  17. 0, 1, 2
  18. 17
  19. 0
  20. 2
  21. 20
  22. 19
  23. 2
  24. Hi, Riya
  25. 40
  26. Hi, Aman
  27. Hi, Kabir
  28. 0
  29. Hi, Arjun
  30. 1
  31. repeats code
  32. 50
  33. 16
  34. 13
  35. 3
  36. 14
  37. Hi, Kabir
  38. 1
  39. 13
  40. 64

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