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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 569 · 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", "Meera", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Aman (d) Hi, Meera
  2. 2.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir (d) Hi, Aman
  3. 3.🔁 What number does this code show?
    let marks = [1, 3, 7, 17, 19];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  4. 4.🔁 What number does this code show?
    let marks = [5, 4, 9, 12, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  5. 5.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Aman (c) Hi, Kabir
  6. 6.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Riya", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Arjun (c) Hi, Aman (d) Hi, Kabir
  7. 7.🔁 What number does this code show?
    let scores = [20, 33, 38, 90];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  8. 8.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 5 (d) 4
  9. 9.🔁 What number does this code show?
    let steps = [6, 16, 1, 5, 5];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  10. 10.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) it is slower (c) less code to write (d) it hides them
  11. 11.🔁 What does a loop do? (a) deletes code (b) draws icons (c) saves photos (d) repeats code
  12. 12.🔁 What number does this code show?
    let scores = [86, 97, 97];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
  14. 14.🔁 What number does this code show?
    let runs = [9, 17, 9, 8, 11];
    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 steps = [5, 3, 14, 15, 2];
    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 = [24, 24, 17];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 What number does this code show?
    let marks = [5, 5, 11, 4];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  18. 18.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Zoya
  19. 19.🔁 What number does this code show?
    let marks = [8, 3, 6, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  20. 20.🔁 What number does this code show?
    let runs = [10, 17, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  21. 21.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Zoya
  22. 22.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Riya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Riya
  23. 23.🔁 What number does this code show?
    let runs = [39, 95, 51];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  24. 24.🔁 What number does this code show?
    let steps = [89, 97, 13];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  25. 25.🔁 What number does this code show?
    let marks = [19, 6, 7];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  26. 26.🔁 What number does this code show?
    let scores = [85, 72, 18, 11, 74];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  27. 27.🔁 What number does this code show?
    let steps = [7, 17, 7, 4];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  28. 28.🔁 What number does this code show?
    let marks = [12, 15, 6, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  29. 29.🔁 What number does this code show?
    let marks = [44, 59, 76];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What number does this code show?
    let steps = [57, 50, 78];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let runs = [9, 4, 13, 8, 14];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  32. 32.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Riya (c) Hi, Aman
  33. 33.🔁 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, Kabir (b) Hi, Meera (c) Hi, Zoya (d) Hi, Riya
  34. 34.🔁 What number does this code show?
    let scores = [3, 16, 5, 15, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  35. 35.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir
  36. 36.🔁 What number does this code show?
    let steps = [5, 3, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  37. 37.🔁 What number does this code show?
    let runs = [10, 6, 4, 7, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  38. 38.🔁 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
  39. 39.🔁 What number does this code show?
    let marks = [43, 10, 12];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  40. 40.🔁 What number does this code show?
    let scores = [45, 81, 16];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. Hi, Arjun
  2. Hi, Aman
  3. 47
  4. 50
  5. Hi, Kabir
  6. Hi, Kabir
  7. 1
  8. 5
  9. 33
  10. less code to write
  11. repeats code
  12. 3
  13. Hi, Kabir
  14. 54
  15. 15
  16. 0
  17. 25
  18. Hi, Meera
  19. 31
  20. 29
  21. Hi, Kabir
  22. Hi, Kabir
  23. 2
  24. 2
  25. 19
  26. 3
  27. 17
  28. 15
  29. 1
  30. 3
  31. 48
  32. Hi, Aman
  33. Hi, Zoya
  34. 16
  35. Hi, Kabir
  36. 20
  37. 43
  38. 0, 1, 2
  39. 1
  40. 1

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