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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 847 · 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 marks = [19, 5, 4];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  2. 2.🔁 What number does this code show?
    let scores = [15, 27, 87];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  3. 3.🔁 What number does this code show?
    let runs = [12, 11, 10, 16, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  4. 4.🔁 What number does this code show?
    let steps = [8, 2, 14, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  5. 5.🔁 What number does this code show?
    let scores = [14, 1, 3, 16];
    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 scores = [4, 3, 16, 19, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  7. 7.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Meera", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Meera (d) Hi, Aman
  8. 8.🔁 What number does this code show?
    let scores = [14, 11, 17, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  9. 9.🔁 What number does this code show?
    let steps = [8, 8, 15, 11];
    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 = [6, 2, 16, 6, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  11. 11.🔁 What number does this code show?
    let scores = [8, 18, 8, 6, 13];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  12. 12.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Aman
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Arjun (d) Hi, Kabir
  14. 14.🔁 What number does this code show?
    let runs = [17, 13, 4, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  15. 15.🔁 What number does this code show?
    let steps = [8, 11, 19, 17];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  16. 16.🔁 What number does this code show?
    let scores = [6, 15, 19, 3, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  17. 17.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Zoya (d) Hi, Arjun
  18. 18.🔁 What number does this code show?
    let scores = [9, 20, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Riya (c) Hi, Arjun (d) Hi, Kabir
  20. 20.🔁 What number does this code show?
    let scores = [18, 18, 16];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  21. 21.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Zoya
  22. 22.🔁 What number does this code show?
    let runs = [18, 12, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  23. 23.🔁 What number does this code show?
    let scores = [14, 9, 7];
    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 runs = [1, 8, 6, 16, 7];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  25. 25.🔁 What number does this code show?
    let scores = [94, 25, 16, 81];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What does a loop do? (a) saves photos (b) repeats code (c) deletes code (d) draws icons
  27. 27.🔁 What number does this code show?
    let runs = [68, 96, 20];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let runs = [56, 37, 54, 20, 65];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What number does this code show?
    let scores = [59, 25, 22, 43, 20];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What number does this code show?
    let steps = [72, 80, 83, 40, 44];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let scores = [5, 16, 16, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  32. 32.🔁 What number does this code show?
    let marks = [13, 81, 23, 85, 71];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What number does this code show?
    let scores = [9, 2, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  34. 34.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it uses more lines (c) less code to write (d) it is slower
  35. 35.🔁 What number does this code show?
    let scores = [17, 5, 10, 5];
    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 = [19, 18, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  37. 37.🔁 What number does this code show?
    let marks = [29, 45, 38, 27];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  38. 38.🔁 list.length tells you ___. (a) the biggest item (b) the first item (c) the last item (d) how many items it has
  39. 39.🔁 What number does this code show?
    let steps = [20, 7, 19, 17, 16];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  40. 40.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Aman (c) Hi, Zoya

Answer key

  1. 28
  2. 1
  3. 61
  4. 26
  5. 34
  6. 43
  7. Hi, Aman
  8. 17
  9. 42
  10. 16
  11. 18
  12. Hi, Arjun
  13. Hi, Arjun
  14. 42
  15. 55
  16. 19
  17. Hi, Riya
  18. 41
  19. Hi, Kabir
  20. 52
  21. Hi, Aman
  22. 42
  23. 14
  24. 38
  25. 2
  26. repeats code
  27. 2
  28. 3
  29. 0
  30. 5
  31. 49
  32. 3
  33. 31
  34. less code to write
  35. 37
  36. 19
  37. 0
  38. how many items it has
  39. 20
  40. Hi, Zoya

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