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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 944 · 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 = ["Zoya", "Kabir", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Zoya (d) Hi, Kabir
  2. 2.🔁 What number does this code show?
    let marks = [91, 52, 75];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  3. 3.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) how many items it has (d) the first item
  4. 4.🔁 What number does this code show?
    let marks = [19, 7, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  5. 5.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 1 (c) 6 (d) 4
  6. 6.🔁 What number does this code show?
    let marks = [11, 19, 3, 13];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  7. 7.🔁 What number does this code show?
    let marks = [11, 10, 2, 1, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  8. 8.🔁 What number does this code show?
    let scores = [34, 35, 90];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  9. 9.🔁 What number does this code show?
    let scores = [79, 10, 41, 38, 74];
    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 steps = [66, 94, 63];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  11. 11.🔁 What number does this code show?
    let runs = [74, 64, 96, 83, 35];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 What number does this code show?
    let marks = [9, 9, 3, 1];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  13. 13.🔁 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
  14. 14.🔁 What number does this code show?
    let runs = [71, 32, 97];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  15. 15.🔁 What number does this code show?
    let steps = [78, 38, 83];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 What number does this code show?
    let runs = [94, 63, 33];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 What number does this code show?
    let steps = [14, 31, 73, 39];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What number does this code show?
    let scores = [11, 72, 78, 23];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  19. 19.🔁 What number does this code show?
    let marks = [12, 44, 76];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  20. 20.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Riya
  21. 21.🔁 What does a loop do? (a) saves photos (b) draws icons (c) deletes code (d) repeats code
  22. 22.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Meera", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
  23. 23.🔁 What number does this code show?
    let steps = [17, 6, 3, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let scores = [16, 18, 3];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  25. 25.🔁 What number does this code show?
    let scores = [66, 98, 47, 47, 48];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What number does this code show?
    let steps = [19, 8, 4];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  27. 27.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Kabir
  28. 28.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Riya (d) Hi, Meera
  29. 29.🔁 What number does this code show?
    let scores = [16, 11, 12, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  30. 30.🔁 What number does this code show?
    let marks = [16, 17, 18, 5, 18];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  31. 31.🔁 What number does this code show?
    let scores = [16, 1, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  32. 32.🔁 What number does this code show?
    let marks = [12, 13, 11, 9, 18];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  33. 33.🔁 What number does this code show?
    let scores = [4, 20, 13, 18, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  34. 34.🔁 What number does this code show?
    let scores = [16, 31, 38, 35, 39];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  35. 35.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Arjun (d) Hi, Aman
  36. 36.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Aman (d) Hi, Zoya
  37. 37.🔁 What number does this code show?
    let marks = [35, 70, 34];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  38. 38.🔁 What number does this code show?
    let scores = [1, 12, 2, 13, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  39. 39.🔁 What number does this code show?
    let scores = [8, 20, 4, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  40. 40.🔁 What number does this code show?
    let runs = [6, 16, 10, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);

Answer key

  1. Hi, Meera
  2. 3
  3. how many items it has
  4. 43
  5. 5
  6. 46
  7. 41
  8. 1
  9. 2
  10. 1
  11. 4
  12. 22
  13. less code to write
  14. 2
  15. 2
  16. 2
  17. 1
  18. 2
  19. 1
  20. Hi, Zoya
  21. repeats code
  22. Hi, Arjun
  23. 17
  24. 18
  25. 2
  26. 19
  27. Hi, Kabir
  28. Hi, Meera
  29. 41
  30. 18
  31. 19
  32. 18
  33. 57
  34. 0
  35. Hi, Zoya
  36. Hi, Aman
  37. 1
  38. 34
  39. 20
  40. 16

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