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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 162 · 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 = ["Meera", "Riya", "Arjun", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya (d) Hi, Aman
  2. 2.🔁 What number does this code show?
    let runs = [1, 3, 4, 3];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  3. 3.🔁 What number does this code show?
    let scores = [18, 39, 14, 10];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  4. 4.🔁 What does a loop do? (a) draws icons (b) saves photos (c) repeats code (d) deletes code
  5. 5.🔁 What number does this code show?
    let runs = [62, 92, 45, 54];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 What number does this code show?
    let marks = [83, 87, 75];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  7. 7.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it uses more lines (c) it hides them (d) less code to write
  8. 8.🔁 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, Arjun (b) Hi, Riya (c) Hi, Zoya
  9. 9.🔁 What number does this code show?
    let scores = [26, 95, 71, 22];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  10. 10.🔁 What number does this code show?
    let marks = [84, 20, 59, 16, 30];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  11. 11.🔁 What number does this code show?
    let scores = [15, 13, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  12. 12.🔁 What number does this code show?
    let steps = [15, 2, 17];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  13. 13.🔁 What number does this code show?
    let scores = [7, 3, 12, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  14. 14.🔁 What number does this code show?
    let steps = [8, 12, 2, 16, 12];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  15. 15.🔁 What number does this code show?
    let steps = [5, 8, 1, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  16. 16.🔁 What number does this code show?
    let marks = [81, 30, 80];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 4 (c) 1 (d) 5
  18. 18.🔁 What number does this code show?
    let scores = [18, 3, 4, 6, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Kabir (c) Hi, Riya
  20. 20.🔁 What number does this code show?
    let runs = [22, 83, 55, 64, 31];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What number does this code show?
    let scores = [15, 5, 19, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  22. 22.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
  23. 23.🔁 What number does this code show?
    let runs = [18, 13, 18, 8];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let steps = [4, 13, 8, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  25. 25.🔁 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
  26. 26.🔁 What number does this code show?
    let steps = [76, 27, 60, 80];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  27. 27.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya
  28. 28.🔁 What number does this code show?
    let runs = [8, 1, 3];
    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 marks = [18, 2, 5, 13];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  30. 30.🔁 What number does this code show?
    let scores = [27, 36, 22];
    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 marks = [48, 75, 87, 63];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  32. 32.🔁 What number does this code show?
    let scores = [61, 31, 42];
    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 runs = [24, 73, 75];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman (d) Hi, Riya
  35. 35.🔁 What number does this code show?
    let steps = [13, 1, 17, 14];
    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 = [85, 18, 31];
    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 runs = [11, 1, 15, 2, 20];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  38. 38.🔁 What number does this code show?
    let marks = [60, 99, 91, 45, 45];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  39. 39.🔁 What number does this code show?
    let scores = [13, 8, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  40. 40.🔁 list.length tells you ___. (a) the first item (b) the biggest item (c) the last item (d) how many items it has

Answer key

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

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