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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 977 · 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 runs = [18, 20, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  2. 2.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Kabir (c) Hi, Aman
  3. 3.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Zoya (c) Hi, Aman (d) Hi, Kabir
  4. 4.🔁 What number does this code show?
    let marks = [20, 20, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  5. 5.🔁 What number does this code show?
    let scores = [9, 2, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  6. 6.🔁 What number does this code show?
    let scores = [1, 15, 10, 3, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  7. 7.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Arjun", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Riya (c) Hi, Aman (d) Hi, Arjun
  8. 8.🔁 What does a loop do? (a) deletes code (b) saves photos (c) draws icons (d) repeats code
  9. 9.🔁 What number does this code show?
    let marks = [71, 73, 10];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  10. 10.🔁 What number does this code show?
    let runs = [8, 7, 19];
    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 = [8, 5, 6];
    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 marks = [67, 76, 63, 67, 45];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What number does this code show?
    let scores = [82, 17, 86, 11, 32];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  14. 14.🔁 What number does this code show?
    let scores = [16, 9, 5, 9, 2];
    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 marks = [7, 2, 5, 8, 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 runs = [41, 91, 57, 12, 50];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 list.length tells you ___. (a) the first item (b) the biggest item (c) how many items it has (d) the last item
  18. 18.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it uses more lines (c) less code to write (d) it hides them
  19. 19.🔁 What number does this code show?
    let steps = [16, 11, 13];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  20. 20.🔁 What number does this code show?
    let steps = [88, 24, 49, 61];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 0, 1, 2, 3 (c) 1, 2, 3 (d) 3
  22. 22.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman
  23. 23.🔁 What number does this code show?
    let marks = [40, 46, 37, 32];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  24. 24.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Meera (c) Hi, Riya (d) Hi, Aman
  25. 25.🔁 What number does this code show?
    let scores = [15, 50, 95, 96];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What number does this code show?
    let marks = [20, 2, 5, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  27. 27.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman
  28. 28.🔁 What number does this code show?
    let marks = [11, 4, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  29. 29.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Meera (d) Hi, Riya
  30. 30.🔁 What number does this code show?
    let steps = [13, 4, 8, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  31. 31.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Meera (c) Hi, Zoya
  32. 32.🔁 What number does this code show?
    let steps = [18, 16, 5, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  33. 33.🔁 What number does this code show?
    let steps = [3, 13, 3, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  34. 34.🔁 What number does this code show?
    let scores = [3, 4, 8, 16, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  35. 35.🔁 What number does this code show?
    let marks = [15, 87, 82];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 4 (c) 5 (d) 6
  37. 37.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Kabir", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Aman (c) Hi, Kabir (d) Hi, Arjun
  38. 38.🔁 What number does this code show?
    let scores = [2, 3, 11, 12, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  39. 39.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Riya", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Kabir (c) Hi, Aman (d) Hi, Zoya
  40. 40.🔁 What number does this code show?
    let runs = [11, 17, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);

Answer key

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

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