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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 519 · 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 = ["Kabir", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Riya (c) Hi, Aman
  2. 2.🔁 Why use a loop to show 100 messages? (a) it hides them (b) less code to write (c) it is slower (d) it uses more lines
  3. 3.🔁 What number does this code show?
    let steps = [55, 51, 26, 97];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  4. 4.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 4 (d) 5
  5. 5.🔁 What number does this code show?
    let steps = [58, 80, 23, 95, 55];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Kabir (c) Hi, Arjun
  7. 7.🔁 What number does this code show?
    let marks = [1, 3, 4, 12];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  8. 8.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya
  9. 9.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Meera (d) Hi, Arjun
  10. 10.🔁 What number does this code show?
    let scores = [18, 8, 17, 4];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  11. 11.🔁 What number does this code show?
    let runs = [11, 19, 16, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  12. 12.🔁 What number does this code show?
    let scores = [58, 30, 87];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What number does this code show?
    let runs = [19, 2, 2, 2];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  14. 14.🔁 What number does this code show?
    let scores = [14, 18, 9, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  15. 15.🔁 What number does this code show?
    let runs = [80, 18, 15];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 What number does this code show?
    let marks = [17, 28, 50, 14];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 What number does this code show?
    let marks = [2, 18, 16, 5];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  18. 18.🔁 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
  19. 19.🔁 What number does this code show?
    let runs = [28, 57, 52];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  20. 20.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Aman (c) Hi, Meera
  21. 21.🔁 What number does this code show?
    let steps = [1, 5, 3, 11, 4];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  22. 22.🔁 list.length tells you ___. (a) the first item (b) the last item (c) how many items it has (d) the biggest item
  23. 23.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Arjun
  24. 24.🔁 What number does this code show?
    let marks = [4, 18, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  25. 25.🔁 What number does this code show?
    let runs = [16, 12, 13];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  26. 26.🔁 What does a loop do? (a) saves photos (b) deletes code (c) repeats code (d) draws icons
  27. 27.🔁 What number does this code show?
    let scores = [12, 3, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  28. 28.🔁 What number does this code show?
    let runs = [17, 10, 19, 18, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  29. 29.🔁 What number does this code show?
    let scores = [10, 17, 13, 3, 4];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  30. 30.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Meera", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya
  31. 31.🔁 What number does this code show?
    let marks = [17, 16, 5, 2, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  32. 32.🔁 What number does this code show?
    let scores = [47, 32, 41, 20, 22];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What number does this code show?
    let scores = [14, 1, 15];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Kabir", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Riya (d) Hi, Aman
  35. 35.🔁 What number does this code show?
    let scores = [84, 38, 70];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let steps = [31, 64, 10, 32, 96];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  37. 37.🔁 What number does this code show?
    let steps = [14, 6, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  38. 38.🔁 What number does this code show?
    let scores = [16, 1, 12];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  39. 39.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Aman", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Meera
  40. 40.🔁 What number does this code show?
    let steps = [48, 78, 18, 25];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. Hi, Aman
  2. less code to write
  3. 1
  4. 5
  5. 2
  6. Hi, Kabir
  7. 20
  8. Hi, Arjun
  9. Hi, Arjun
  10. 47
  11. 19
  12. 1
  13. 19
  14. 42
  15. 1
  16. 0
  17. 41
  18. 0, 1, 2
  19. 2
  20. Hi, Riya
  21. 11
  22. how many items it has
  23. Hi, Aman
  24. 32
  25. 16
  26. repeats code
  27. 27
  28. 84
  29. 47
  30. Hi, Zoya
  31. 60
  32. 2
  33. 15
  34. Hi, Riya
  35. 2
  36. 2
  37. 14
  38. 16
  39. Hi, Zoya
  40. 1

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