← Loops over lists lesson New set →

App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 598 · 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 = [7, 2, 1, 8, 8];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  2. 2.🔁 What number does this code show?
    let runs = [5, 19, 19, 3];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  3. 3.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Meera (d) Hi, Arjun
  4. 4.🔁 What does a loop do? (a) saves photos (b) draws icons (c) repeats code (d) deletes code
  5. 5.🔁 What number does this code show?
    let scores = [4, 2, 19, 9];
    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 runs = [95, 32, 31];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  7. 7.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 1, 2, 3 (c) 0, 1, 2, 3 (d) 0, 1, 2
  8. 8.🔁 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
  9. 9.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) how many items it has (d) the first item
  10. 10.🔁 What number does this code show?
    let runs = [3, 17, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  11. 11.🔁 What number does this code show?
    let steps = [15, 4, 20, 7];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  12. 12.🔁 What number does this code show?
    let scores = [34, 80, 33, 24];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What number does this code show?
    let marks = [18, 17, 10, 7];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  14. 14.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Riya (c) Hi, Meera
  15. 15.🔁 What number does this code show?
    let steps = [10, 1, 4, 12];
    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 = [20, 6, 6, 9, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  17. 17.🔁 What number does this code show?
    let steps = [76, 96, 97, 89];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What number does this code show?
    let marks = [16, 11, 1, 13];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  19. 19.🔁 What number does this code show?
    let marks = [3, 5, 10, 5, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  20. 20.🔁 What number does this code show?
    let runs = [12, 19, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  21. 21.🔁 What number does this code show?
    let marks = [16, 10, 12];
    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 steps = [17, 68, 13];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  23. 23.🔁 What number does this code show?
    let scores = [98, 72, 15, 97, 25];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  24. 24.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Aman
  25. 25.🔁 What number does this code show?
    let steps = [4, 17, 1];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Meera (c) Hi, Riya
  27. 27.🔁 What number does this code show?
    let steps = [78, 38, 19, 24];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Arjun", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Aman
  29. 29.🔁 What number does this code show?
    let runs = [12, 7, 3, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  30. 30.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Kabir
  31. 31.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Aman (c) Hi, Meera
  32. 32.🔁 What number does this code show?
    let steps = [9, 3, 9, 8, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  33. 33.🔁 What number does this code show?
    let runs = [2, 19, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Aman", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Meera (d) Hi, Aman
  35. 35.🔁 What number does this code show?
    let steps = [28, 83, 22, 98, 41];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let scores = [18, 3, 17];
    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 steps = [52, 17, 70, 63];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  38. 38.🔁 What number does this code show?
    let marks = [11, 17, 2, 19];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  39. 39.🔁 What number does this code show?
    let scores = [10, 61, 63, 97];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  40. 40.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Zoya (d) Hi, Arjun

Answer key

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

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