← Loops over lists lesson New set →

App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 927 · 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 = [77, 10, 95];
    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 scores = [2, 16, 16, 3, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  3. 3.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Aman", "Zoya", "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
  4. 4.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the biggest item (d) the first item
  5. 5.🔁 What number does this code show?
    let steps = [17, 7, 20, 15];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  6. 6.🔁 What number does this code show?
    let scores = [6, 9, 3, 6, 11];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  7. 7.🔁 What number does this code show?
    let scores = [5, 16, 7, 3, 16];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  8. 8.🔁 What number does this code show?
    let runs = [5, 7, 10, 20, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  9. 9.🔁 What number does this code show?
    let runs = [7, 5, 12];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  10. 10.🔁 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, Kabir (b) Hi, Riya (c) Hi, Zoya
  11. 11.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 3 (c) 1, 2, 3 (d) 0, 1, 2
  12. 12.🔁 What number does this code show?
    let marks = [9, 4, 8, 1, 6];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  13. 13.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it uses more lines (c) it is slower (d) it hides them
  14. 14.🔁 What number does this code show?
    let marks = [30, 23, 85, 38, 30];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  15. 15.🔁 What number does this code show?
    let runs = [7, 15, 2, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  16. 16.🔁 What number does this code show?
    let steps = [95, 35, 27, 32];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 What number does this code show?
    let runs = [4, 10, 3, 8, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  18. 18.🔁 What number does this code show?
    let runs = [4, 20, 14, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  19. 19.🔁 What number does this code show?
    let runs = [74, 36, 20, 21, 76];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  20. 20.🔁 What does a loop do? (a) saves photos (b) repeats code (c) draws icons (d) deletes code
  21. 21.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
  22. 22.🔁 What number does this code show?
    let scores = [4, 6, 9, 4];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  23. 23.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Arjun (c) Hi, Aman
  24. 24.🔁 What number does this code show?
    let steps = [9, 15, 15, 5, 5];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  25. 25.🔁 What number does this code show?
    let runs = [39, 49, 29, 65, 36];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What number does this code show?
    let runs = [13, 5, 14];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  27. 27.🔁 What number does this code show?
    let marks = [34, 96, 39, 94, 62];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let marks = [71, 28, 67, 47];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
  30. 30.🔁 What number does this code show?
    let runs = [29, 39, 92, 19];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let marks = [5, 17, 12, 2];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  32. 32.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Riya", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir (d) Hi, Aman
  33. 33.🔁 What number does this code show?
    let scores = [11, 2, 16];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  34. 34.🔁 What number does this code show?
    let scores = [6, 16, 5, 5, 11];
    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 steps = [8, 17, 5];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  36. 36.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Arjun", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Zoya (c) Hi, Riya (d) Hi, Arjun
  37. 37.🔁 What number does this code show?
    let steps = [15, 11, 16];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  38. 38.🔁 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, Zoya (b) Hi, Aman (c) Hi, Arjun (d) Hi, Riya
  39. 39.🔁 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, Kabir (b) Hi, Aman (c) Hi, Zoya (d) Hi, Arjun
  40. 40.🔁 What number does this code show?
    let marks = [11, 16, 2];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);

Answer key

  1. 2
  2. 47
  3. Hi, Arjun
  4. how many items it has
  5. 59
  6. 35
  7. 16
  8. 43
  9. 12
  10. Hi, Zoya
  11. 0, 1, 2
  12. 28
  13. less code to write
  14. 1
  15. 36
  16. 1
  17. 31
  18. 47
  19. 2
  20. repeats code
  21. Hi, Arjun
  22. 9
  23. Hi, Arjun
  24. 15
  25. 0
  26. 14
  27. 2
  28. 3
  29. 5
  30. 1
  31. 36
  32. Hi, Kabir
  33. 29
  34. 16
  35. 17
  36. Hi, Riya
  37. 16
  38. Hi, Arjun
  39. Hi, Arjun
  40. 16

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students