← Loops over lists lesson New set →

App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 686 · 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 runs = [31, 10, 31, 65];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  2. 2.🔁 What number does this code show?
    let marks = [13, 4, 11, 16];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  3. 3.🔁 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
  4. 4.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2, 3 (c) 0, 1, 2 (d) 1, 2, 3
  5. 5.🔁 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, Meera (b) Hi, Aman (c) Hi, Kabir (d) Hi, Riya
  6. 6.🔁 What number does this code show?
    let steps = [60, 49, 18, 14];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  7. 7.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Aman (c) Hi, Riya (d) Hi, Arjun
  8. 8.🔁 What number does this code show?
    let scores = [15, 3, 12, 16];
    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 scores = [1, 7, 10, 9, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  10. 10.🔁 What number does this code show?
    let scores = [20, 3, 11, 20];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  11. 11.🔁 What number does this code show?
    let marks = [11, 4, 18];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  12. 12.🔁 What number does this code show?
    let marks = [6, 5, 8, 1];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  13. 13.🔁 What number does this code show?
    let steps = [58, 63, 87, 74, 63];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  14. 14.🔁 What number does this code show?
    let runs = [4, 2, 7, 6, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  15. 15.🔁 list.length tells you ___. (a) the first item (b) the last item (c) the biggest item (d) how many items it has
  16. 16.🔁 What number does this code show?
    let scores = [5, 9, 4];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  17. 17.🔁 What does a loop do? (a) saves photos (b) draws icons (c) repeats code (d) deletes code
  18. 18.🔁 What number does this code show?
    let runs = [2, 3, 13, 4];
    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 steps = [6, 20, 12, 16, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  20. 20.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Aman (c) Hi, Meera (d) Hi, Arjun
  21. 21.🔁 What number does this code show?
    let marks = [16, 16, 5];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  22. 22.🔁 What number does this code show?
    let marks = [18, 20, 18, 8, 18];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  23. 23.🔁 What number does this code show?
    let runs = [98, 38, 98, 30];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  24. 24.🔁 What number does this code show?
    let scores = [8, 16, 9, 5, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  25. 25.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Meera (c) Hi, Zoya
  26. 26.🔁 What number does this code show?
    let runs = [2, 20, 16, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  27. 27.🔁 What number does this code show?
    let marks = [7, 16, 4, 16];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  28. 28.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Arjun", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Zoya
  29. 29.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Arjun", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Aman (c) Hi, Arjun (d) Hi, Kabir
  30. 30.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Arjun", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Aman (d) Hi, Riya
  31. 31.🔁 What number does this code show?
    let steps = [79, 75, 43, 66, 56];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  32. 32.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Kabir
  33. 33.🔁 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, Zoya (b) Hi, Riya (c) Hi, Arjun
  34. 34.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 5 (d) 6
  35. 35.🔁 What number does this code show?
    let marks = [19, 14, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  36. 36.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Meera", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Meera (d) Hi, Arjun
  37. 37.🔁 What number does this code show?
    let runs = [15, 13, 3, 8, 11];
    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 marks = [6, 11, 11, 16];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  39. 39.🔁 What number does this code show?
    let steps = [17, 8, 7];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let scores = [13, 4, 5, 19];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

Answer key

  1. 1
  2. 16
  3. less code to write
  4. 0, 1, 2
  5. Hi, Kabir
  6. 1
  7. Hi, Aman
  8. 46
  9. 10
  10. 20
  11. 33
  12. 20
  13. 5
  14. 16
  15. how many items it has
  16. 9
  17. repeats code
  18. 22
  19. 20
  20. Hi, Meera
  21. 37
  22. 20
  23. 2
  24. 41
  25. Hi, Zoya
  26. 46
  27. 43
  28. Hi, Aman
  29. Hi, Aman
  30. Hi, Riya
  31. 3
  32. Hi, Meera
  33. Hi, Zoya
  34. 5
  35. 53
  36. Hi, Arjun
  37. 50
  38. 44
  39. 32
  40. 19

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