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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 290 · 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 steps = [8, 4, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  2. 2.🔁 What number does this code show?
    let steps = [2, 16, 2, 11, 11];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  3. 3.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Arjun", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Aman (c) Hi, Kabir (d) Hi, Riya
  4. 4.🔁 What number does this code show?
    let scores = [7, 5, 4, 2, 12];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  5. 5.🔁 What number does this code show?
    let steps = [3, 13, 4, 8, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  6. 6.🔁 What number does this code show?
    let runs = [9, 4, 16, 6, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  7. 7.🔁 What number does this code show?
    let steps = [86, 72, 28, 15, 83];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  8. 8.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 1 (c) 6 (d) 4
  9. 9.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Zoya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Riya
  10. 10.🔁 What number does this code show?
    let marks = [20, 14, 18, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  11. 11.🔁 What number does this code show?
    let steps = [35, 20, 48, 78, 67];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 What number does this code show?
    let runs = [10, 18, 11];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  13. 13.🔁 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
  14. 14.🔁 What number does this code show?
    let runs = [8, 10, 14, 19, 15];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  15. 15.🔁 What number does this code show?
    let marks = [2, 2, 2, 11];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  16. 16.🔁 What number does this code show?
    let steps = [1, 10, 3, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  17. 17.🔁 list.length tells you ___. (a) how many items it has (b) the biggest item (c) the first item (d) the last item
  18. 18.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it hides them (c) less code to write (d) it uses more lines
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun
  20. 20.🔁 What number does this code show?
    let steps = [12, 26, 58, 26, 42];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Riya", "Meera", "Kabir"];
    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 is the LAST line this code shows?
    let names = ["Kabir", "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, Meera
  23. 23.🔁 What number does this code show?
    let scores = [11, 13, 20, 7, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let marks = [1, 8, 18, 14, 8];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  25. 25.🔁 What number does this code show?
    let steps = [3, 2, 7];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  26. 26.🔁 What number does this code show?
    let scores = [4, 8, 9, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  27. 27.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Riya (d) Hi, Meera
  28. 28.🔁 What number does this code show?
    let runs = [5, 11, 14, 2, 14];
    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 steps = [78, 15, 80];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Kabir (b) Hi, Aman (c) Hi, Arjun
  31. 31.🔁 What number does this code show?
    let steps = [9, 4, 14, 14, 8];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  32. 32.🔁 What number does this code show?
    let steps = [11, 9, 8];
    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 = [5, 2, 13, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  34. 34.🔁 What does a loop do? (a) repeats code (b) saves photos (c) draws icons (d) deletes code
  35. 35.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Meera (c) Hi, Aman
  36. 36.🔁 What number does this code show?
    let marks = [31, 54, 82];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  37. 37.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman (d) Hi, Meera
  38. 38.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }
    (a) Hi, Aman (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Riya
  39. 39.🔁 What number does this code show?
    let steps = [11, 14, 12, 18];
    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 steps = [12, 6, 10, 13];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);

Answer key

  1. 19
  2. 16
  3. Hi, Riya
  4. 12
  5. 18
  6. 36
  7. 3
  8. 5
  9. Hi, Arjun
  10. 62
  11. 3
  12. 39
  13. 0, 1, 2
  14. 66
  15. 17
  16. 33
  17. how many items it has
  18. less code to write
  19. Hi, Meera
  20. 0
  21. Hi, Kabir
  22. Hi, Aman
  23. 20
  24. 18
  25. 12
  26. 28
  27. Hi, Zoya
  28. 46
  29. 2
  30. Hi, Arjun
  31. 49
  32. 28
  33. 29
  34. repeats code
  35. Hi, Aman
  36. 1
  37. Hi, Zoya
  38. Hi, Kabir
  39. 55
  40. 41

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