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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 266 · 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 steps = [7, 1, 14];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  2. 2.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Aman (c) Hi, Kabir (d) Hi, Arjun
  3. 3.🔁 What number does this code show?
    let steps = [6, 12, 1, 20];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  4. 4.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Meera (c) Hi, Kabir (d) Hi, Aman
  5. 5.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 4 (c) 5 (d) 6
  6. 6.🔁 What number does this code show?
    let scores = [9, 19, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  7. 7.🔁 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
  8. 8.🔁 What number does this code show?
    let scores = [9, 20, 13];
    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 steps = [9, 20, 2, 8, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  10. 10.🔁 What number does this code show?
    let steps = [12, 15, 2, 2, 1];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  11. 11.🔁 What does a loop do? (a) deletes code (b) saves photos (c) repeats code (d) draws icons
  12. 12.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Zoya (c) Hi, Arjun
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Kabir (c) Hi, Zoya
  14. 14.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya
  15. 15.🔁 What number does this code show?
    let runs = [7, 4, 18];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  16. 16.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Kabir", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Zoya (b) Hi, Riya (c) Hi, Kabir (d) Hi, Meera
  17. 17.🔁 What number does this code show?
    let scores = [10, 4, 1, 19, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  18. 18.🔁 What number does this code show?
    let steps = [20, 4, 6, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Aman", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Aman (c) Hi, Zoya (d) Hi, Riya
  20. 20.🔁 What number does this code show?
    let scores = [5, 10, 6, 12, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  21. 21.🔁 What number does this code show?
    let steps = [59, 12, 23];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  22. 22.🔁 What number does this code show?
    let runs = [8, 7, 15];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  23. 23.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Riya (b) Hi, Aman (c) Hi, Zoya (d) Hi, Meera
  24. 24.🔁 What number does this code show?
    let scores = [42, 67, 63, 93];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  25. 25.🔁 What number does this code show?
    let scores = [20, 6, 17];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  26. 26.🔁 What number does this code show?
    let scores = [3, 11, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  27. 27.🔁 What number does this code show?
    let steps = [88, 16, 36, 31, 91];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let steps = [45, 50, 70, 18, 49];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Meera (c) Hi, Riya
  30. 30.🔁 What number does this code show?
    let scores = [6, 3, 4];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[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 is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Aman (b) Hi, Kabir (c) Hi, Arjun
  33. 33.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun
  34. 34.🔁 What number does this code show?
    let marks = [13, 16, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  35. 35.🔁 What number does this code show?
    let runs = [20, 21, 80, 58];
    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 = [17, 16, 7, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  37. 37.🔁 What number does this code show?
    let steps = [12, 31, 55, 30, 29];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  38. 38.🔁 What number does this code show?
    let steps = [15, 9, 15, 18, 15];
    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 scores = [7, 8, 17];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let scores = [18, 13, 4, 4, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

Answer key

  1. 22
  2. Hi, Arjun
  3. 39
  4. Hi, Meera
  5. 5
  6. 40
  7. 0, 1, 2
  8. 42
  9. 48
  10. 32
  11. repeats code
  12. Hi, Zoya
  13. Hi, Zoya
  14. Hi, Riya
  15. 18
  16. Hi, Riya
  17. 19
  18. 36
  19. Hi, Arjun
  20. 40
  21. 1
  22. 30
  23. Hi, Meera
  24. 3
  25. 43
  26. 15
  27. 2
  28. 1
  29. Hi, Arjun
  30. 13
  31. Hi, Arjun
  32. Hi, Kabir
  33. Hi, Meera
  34. 43
  35. 2
  36. 54
  37. 0
  38. 18
  39. 32
  40. 18

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