← Loops over lists lesson New set →

App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 227 · 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", "Meera", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Meera
  2. 2.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Aman (d) Hi, Arjun
  3. 3.🔁 What number does this code show?
    let steps = [72, 59, 38, 64, 59];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  4. 4.🔁 What number does this code show?
    let runs = [4, 15, 3];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  5. 5.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 1, 2, 3 (c) 3 (d) 0, 1, 2, 3
  6. 6.🔁 What number does this code show?
    let scores = [10, 17, 15, 15, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  7. 7.🔁 What number does this code show?
    let steps = [14, 19, 4, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  8. 8.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 5 (c) 6 (d) 1
  9. 9.🔁 What number does this code show?
    let scores = [65, 22, 79];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  10. 10.🔁 What number does this code show?
    let scores = [1, 19, 10];
    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 = [18, 5, 14, 20];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  12. 12.🔁 What number does this code show?
    let runs = [14, 17, 20, 19, 6];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  13. 13.🔁 What number does this code show?
    let scores = [14, 14, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  14. 14.🔁 What number does this code show?
    let scores = [1, 3, 12, 12];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  15. 15.🔁 What number does this code show?
    let runs = [83, 20, 21, 30];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 What number does this code show?
    let runs = [17, 18, 8, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  17. 17.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Aman
  18. 18.🔁 What number does this code show?
    let marks = [94, 27, 36];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  19. 19.🔁 What number does this code show?
    let scores = [11, 15, 19, 18, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  20. 20.🔁 What does a loop do? (a) repeats code (b) draws icons (c) saves photos (d) deletes code
  21. 21.🔁 What number does this code show?
    let scores = [7, 10, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  22. 22.🔁 What number does this code show?
    let marks = [6, 9, 16, 20, 11];
    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 marks = [5, 4, 3, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  24. 24.🔁 What number does this code show?
    let runs = [13, 2, 8, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  25. 25.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the first item (d) the biggest item
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Arjun
  27. 27.🔁 What number does this code show?
    let marks = [85, 75, 44, 56, 74];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let scores = [17, 6, 2, 4, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  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, Riya (b) Hi, Meera (c) Hi, Arjun
  30. 30.🔁 What number does this code show?
    let scores = [42, 64, 78, 63];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let scores = [69, 14, 91];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  32. 32.🔁 What number does this code show?
    let runs = [80, 27, 15, 19];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What number does this code show?
    let runs = [19, 99, 69];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  34. 34.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it is slower (c) it hides them (d) it uses more lines
  35. 35.🔁 What number does this code show?
    let steps = [12, 14, 13, 16, 20];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  36. 36.🔁 What number does this code show?
    let steps = [35, 50, 18];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  37. 37.🔁 What number does this code show?
    let scores = [18, 14, 5, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  38. 38.🔁 What number does this code show?
    let steps = [5, 3, 16];
    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 runs = [20, 4, 2, 10, 15];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  40. 40.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Meera (d) Hi, Kabir

Answer key

  1. Hi, Kabir
  2. Hi, Kabir
  3. 4
  4. 22
  5. 0, 1, 2
  6. 17
  7. 39
  8. 5
  9. 1
  10. 19
  11. 20
  12. 20
  13. 29
  14. 12
  15. 1
  16. 47
  17. Hi, Kabir
  18. 1
  19. 81
  20. repeats code
  21. 10
  22. 20
  23. 22
  24. 31
  25. how many items it has
  26. Hi, Arjun
  27. 3
  28. 49
  29. Hi, Arjun
  30. 1
  31. 1
  32. 1
  33. 2
  34. less code to write
  35. 20
  36. 0
  37. 52
  38. 16
  39. 51
  40. Hi, Riya

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