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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 333 · 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 steps = [1, 13, 12, 7];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  2. 2.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Arjun (c) Hi, Meera (d) Hi, Kabir
  3. 3.🔁 What number does this code show?
    let steps = [29, 23, 79, 46, 99];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  4. 4.🔁 What number does this code show?
    let scores = [3, 11, 13, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  5. 5.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 6 (c) 4 (d) 5
  6. 6.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 0, 1, 2 (c) 1, 2, 3 (d) 3
  7. 7.🔁 What number does this code show?
    let steps = [15, 10, 4, 1];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  8. 8.🔁 What number does this code show?
    let scores = [20, 4, 18, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  9. 9.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Zoya", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Meera (d) Hi, Arjun
  10. 10.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Riya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Arjun (c) Hi, Meera (d) Hi, Aman
  11. 11.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it hides them (c) less code to write (d) it uses more lines
  12. 12.🔁 What number does this code show?
    let scores = [89, 54, 65];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Zoya (d) Hi, Meera
  14. 14.🔁 list.length tells you ___. (a) the biggest item (b) how many items it has (c) the first item (d) the last item
  15. 15.🔁 What number does this code show?
    let marks = [9, 7, 7, 14, 4];
    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 marks = [11, 5, 2];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  17. 17.🔁 What number does this code show?
    let marks = [11, 7, 12];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  18. 18.🔁 What number does this code show?
    let runs = [5, 18, 17, 18];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  19. 19.🔁 What number does this code show?
    let scores = [12, 3, 10, 14];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  20. 20.🔁 What number does this code show?
    let steps = [16, 13, 16, 1];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  21. 21.🔁 What number does this code show?
    let marks = [1, 3, 5, 13];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  22. 22.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Aman (d) Hi, Kabir
  23. 23.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Riya", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Riya (d) Hi, Aman
  24. 24.🔁 What number does this code show?
    let steps = [52, 32, 11];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  25. 25.🔁 What number does this code show?
    let steps = [42, 38, 34, 50, 25];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  26. 26.🔁 What number does this code show?
    let scores = [79, 16, 36, 76];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  27. 27.🔁 What number does this code show?
    let scores = [13, 20, 10, 20];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  28. 28.🔁 What number does this code show?
    let runs = [66, 37, 51, 90];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What number does this code show?
    let runs = [14, 9, 18, 15, 18];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  30. 30.🔁 What number does this code show?
    let runs = [16, 9, 15, 14, 14];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  31. 31.🔁 What does a loop do? (a) draws icons (b) saves photos (c) deletes code (d) repeats code
  32. 32.🔁 What number does this code show?
    let scores = [8, 14, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  33. 33.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun (d) Hi, Aman
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Meera
  35. 35.🔁 What number does this code show?
    let runs = [15, 1, 19];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  36. 36.🔁 What number does this code show?
    let steps = [12, 7, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  37. 37.🔁 What number does this code show?
    let steps = [5, 20, 5, 15];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  38. 38.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Riya (c) Hi, Aman
  39. 39.🔁 What number does this code show?
    let scores = [19, 5, 8, 3, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  40. 40.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Kabir", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Aman (c) Hi, Kabir (d) Hi, Riya

Answer key

  1. 33
  2. Hi, Kabir
  3. 2
  4. 37
  5. 5
  6. 0, 1, 2
  7. 15
  8. 47
  9. Hi, Arjun
  10. Hi, Aman
  11. less code to write
  12. 1
  13. Hi, Zoya
  14. how many items it has
  15. 41
  16. 11
  17. 12
  18. 58
  19. 14
  20. 46
  21. 13
  22. Hi, Riya
  23. Hi, Aman
  24. 0
  25. 1
  26. 2
  27. 20
  28. 2
  29. 74
  30. 68
  31. repeats code
  32. 29
  33. Hi, Riya
  34. Hi, Meera
  35. 35
  36. 19
  37. 20
  38. Hi, Zoya
  39. 49
  40. Hi, Riya

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