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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 109 · 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 = ["Arjun", "Zoya", "Riya", "Aman", "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
  2. 2.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 4 (c) 1 (d) 5
  3. 3.🔁 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, Arjun (b) Hi, Aman (c) Hi, Kabir
  4. 4.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the first item (d) the biggest item
  5. 5.🔁 What number does this code show?
    let scores = [8, 7, 3, 10, 11];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  6. 6.🔁 What number does this code show?
    let steps = [12, 20, 3, 2, 10];
    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 = [15, 68, 82];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  8. 8.🔁 What does a loop do? (a) deletes code (b) draws icons (c) repeats code (d) saves photos
  9. 9.🔁 What number does this code show?
    let scores = [8, 17, 13, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  10. 10.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Riya
  11. 11.🔁 What number does this code show?
    let scores = [14, 2, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  12. 12.🔁 What number does this code show?
    let runs = [9, 15, 3, 6];
    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 = [13, 3, 3, 20];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  14. 14.🔁 What number does this code show?
    let steps = [85, 54, 25];
    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 steps = [60, 54, 79, 22];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it is slower (c) it uses more lines (d) it hides them
  17. 17.🔁 What number does this code show?
    let steps = [2, 8, 15, 20];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  18. 18.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Zoya (d) Hi, Aman
  20. 20.🔁 What number does this code show?
    let scores = [5, 12, 5, 20];
    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 scores = [4, 7, 4, 10, 16];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  22. 22.🔁 What number does this code show?
    let scores = [19, 16, 4];
    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 runs = [17, 5, 3];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let steps = [23, 72, 39, 94];
    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 scores = [90, 22, 10];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman
  27. 27.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 1, 2, 3 (c) 0, 1, 2 (d) 0, 1, 2, 3
  28. 28.🔁 What number does this code show?
    let runs = [57, 75, 13, 93, 77];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What number does this code show?
    let marks = [61, 40, 12, 61, 87];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What number does this code show?
    let scores = [17, 11, 7, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  31. 31.🔁 What number does this code show?
    let steps = [10, 9, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  32. 32.🔁 What number does this code show?
    let runs = [7, 1, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  33. 33.🔁 What number does this code show?
    let runs = [6, 6, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  34. 34.🔁 What number does this code show?
    let scores = [4, 1, 1, 13];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  35. 35.🔁 What number does this code show?
    let scores = [2, 1, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  36. 36.🔁 What number does this code show?
    let scores = [64, 42, 35];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  37. 37.🔁 What number does this code show?
    let runs = [12, 1, 18, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  38. 38.🔁 What number does this code show?
    let scores = [8, 8, 5, 9];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  39. 39.🔁 What number does this code show?
    let steps = [10, 17, 20, 3, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  40. 40.🔁 What number does this code show?
    let scores = [48, 70, 62, 19];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. Hi, Kabir
  2. 5
  3. Hi, Arjun
  4. how many items it has
  5. 39
  6. 20
  7. 2
  8. repeats code
  9. 17
  10. Hi, Zoya
  11. 17
  12. 33
  13. 39
  14. 1
  15. 1
  16. less code to write
  17. 20
  18. Hi, Aman
  19. Hi, Aman
  20. 42
  21. 41
  22. 39
  23. 17
  24. 2
  25. 1
  26. Hi, Meera
  27. 0, 1, 2
  28. 4
  29. 4
  30. 17
  31. 38
  32. 7
  33. 18
  34. 19
  35. 17
  36. 1
  37. 33
  38. 30
  39. 20
  40. 1

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