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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 578 · 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.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2 (c) 0, 1, 2, 3 (d) 1, 2, 3
  2. 2.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Kabir (c) Hi, Riya
  3. 3.🔁 What number does this code show?
    let steps = [44, 75, 71];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  4. 4.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) the first item (d) how many items it has
  5. 5.🔁 What number does this code show?
    let scores = [3, 5, 10, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  6. 6.🔁 What number does this code show?
    let scores = [19, 2, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  7. 7.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) less code to write (c) it is slower (d) it hides them
  8. 8.🔁 What number does this code show?
    let runs = [98, 75, 70, 62];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  9. 9.🔁 What number does this code show?
    let steps = [18, 7, 15, 13, 11];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  10. 10.🔁 What number does this code show?
    let scores = [20, 14, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  11. 11.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Kabir", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Meera (d) Hi, Aman
  12. 12.🔁 What number does this code show?
    let marks = [3, 14, 14];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  13. 13.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Meera
  14. 14.🔁 What number does this code show?
    let scores = [7, 14, 2, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  15. 15.🔁 What does a loop do? (a) draws icons (b) repeats code (c) deletes code (d) saves photos
  16. 16.🔁 What number does this code show?
    let runs = [8, 12, 1, 19];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  17. 17.🔁 What number does this code show?
    let scores = [16, 15, 8, 2, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  18. 18.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 5 (d) 1
  19. 19.🔁 What number does this code show?
    let runs = [15, 1, 17, 5];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  20. 20.🔁 What number does this code show?
    let steps = [38, 32, 94, 30];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What number does this code show?
    let marks = [16, 3, 3];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  22. 22.🔁 What number does this code show?
    let scores = [12, 13, 4, 2, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  23. 23.🔁 What number does this code show?
    let runs = [19, 4, 1, 11];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let runs = [20, 7, 15, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  25. 25.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Aman", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Riya (c) Hi, Meera (d) Hi, Zoya
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir
  27. 27.🔁 What number does this code show?
    let steps = [14, 66, 18, 86];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let steps = [70, 56, 87, 39];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What number does this code show?
    let scores = [10, 3, 1];
    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 steps = [8, 7, 10];
    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 = ["Arjun", "Riya", "Meera", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
  32. 32.🔁 What number does this code show?
    let runs = [5, 3, 11, 1, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  33. 33.🔁 What number does this code show?
    let marks = [17, 21, 36, 13, 34];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  34. 34.🔁 What number does this code show?
    let scores = [16, 3, 15, 12, 15];
    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 scores = [11, 1, 9];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  36. 36.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun (d) Hi, Aman
  37. 37.🔁 What number does this code show?
    let scores = [15, 15, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  38. 38.🔁 What number does this code show?
    let marks = [18, 5, 1, 20, 16];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  39. 39.🔁 What number does this code show?
    let steps = [5, 14, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let steps = [1, 4, 4, 4];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);

Answer key

  1. 0, 1, 2
  2. Hi, Kabir
  3. 2
  4. how many items it has
  5. 32
  6. 19
  7. less code to write
  8. 4
  9. 18
  10. 20
  11. Hi, Arjun
  12. 14
  13. Hi, Kabir
  14. 43
  15. repeats code
  16. 19
  17. 16
  18. 5
  19. 38
  20. 1
  21. 16
  22. 51
  23. 19
  24. 52
  25. Hi, Meera
  26. Hi, Riya
  27. 2
  28. 2
  29. 14
  30. 25
  31. Hi, Aman
  32. 26
  33. 0
  34. 61
  35. 11
  36. Hi, Arjun
  37. 33
  38. 20
  39. 38
  40. 13

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