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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 984 · 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 = ["Riya", "Zoya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Riya (d) Hi, Kabir
  2. 2.🔁 What number does this code show?
    let marks = [17, 90, 77];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  3. 3.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 3 (d) 0, 1, 2
  4. 4.🔁 What number does this code show?
    let marks = [51, 13, 67, 52];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  5. 5.🔁 What number does this code show?
    let scores = [73, 24, 45];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 What number does this code show?
    let steps = [11, 14, 15, 16];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  7. 7.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Riya (c) Hi, Meera (d) Hi, Aman
  8. 8.🔁 What does a loop do? (a) draws icons (b) deletes code (c) saves photos (d) repeats code
  9. 9.🔁 What number does this code show?
    let scores = [12, 19, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  10. 10.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Zoya (d) Hi, Kabir
  11. 11.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it is slower (c) it uses more lines (d) less code to write
  12. 12.🔁 What number does this code show?
    let steps = [17, 14, 12, 11, 10];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  13. 13.🔁 What number does this code show?
    let marks = [18, 18, 9, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  14. 14.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Meera (d) Hi, Aman
  15. 15.🔁 What number does this code show?
    let steps = [82, 25, 31, 70];
    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 steps = [15, 19, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  17. 17.🔁 What number does this code show?
    let runs = [12, 54, 57];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Aman (c) Hi, Meera (d) Hi, Zoya
  19. 19.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Arjun", "Zoya", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Meera
  20. 20.🔁 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, Aman (b) Hi, Arjun (c) Hi, Zoya
  21. 21.🔁 What number does this code show?
    let steps = [12, 7, 1, 3, 1];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  22. 22.🔁 What number does this code show?
    let marks = [12, 18, 63, 82, 48];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  23. 23.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 5 (c) 6 (d) 4
  24. 24.🔁 What number does this code show?
    let scores = [4, 13, 10, 9, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  25. 25.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) how many items it has (d) the first item
  26. 26.🔁 What number does this code show?
    let steps = [32, 61, 42];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  27. 27.🔁 What number does this code show?
    let runs = [23, 57, 29, 76];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let steps = [15, 10, 73];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What number does this code show?
    let steps = [4, 2, 11, 1, 8];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  30. 30.🔁 What number does this code show?
    let steps = [15, 21, 43, 11, 81];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun
  32. 32.🔁 What number does this code show?
    let steps = [17, 14, 7, 2];
    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 marks = [66, 43, 24];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Meera (c) Hi, Riya (d) Hi, Kabir
  35. 35.🔁 What number does this code show?
    let steps = [30, 61, 24, 44, 96];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let runs = [17, 18, 8, 18];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  37. 37.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Aman", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Riya (d) Hi, Kabir
  38. 38.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Aman (c) Hi, Riya (d) Hi, Kabir
  39. 39.🔁 What number does this code show?
    let runs = [12, 11, 14, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let runs = [57, 49, 31];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. Hi, Kabir
  2. 2
  3. 0, 1, 2
  4. 1
  5. 2
  6. 56
  7. Hi, Kabir
  8. repeats code
  9. 34
  10. Hi, Arjun
  11. less code to write
  12. 64
  13. 18
  14. Hi, Aman
  15. 2
  16. 19
  17. 0
  18. Hi, Aman
  19. Hi, Meera
  20. Hi, Zoya
  21. 12
  22. 2
  23. 5
  24. 39
  25. how many items it has
  26. 1
  27. 2
  28. 1
  29. 26
  30. 1
  31. Hi, Riya
  32. 40
  33. 2
  34. Hi, Meera
  35. 2
  36. 18
  37. Hi, Zoya
  38. Hi, Arjun
  39. 38
  40. 0

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