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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 542 · 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 = ["Kabir", "Aman", "Meera", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman (d) Hi, Zoya
  2. 2.🔁 What number does this code show?
    let steps = [68, 68, 92, 22, 21];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        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) 3 (c) 0, 1, 2, 3 (d) 0, 1, 2
  4. 4.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Riya", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Meera (d) Hi, Riya
  5. 5.🔁 What number does this code show?
    let scores = [76, 80, 12];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 What number does this code show?
    let scores = [4, 8, 19, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  7. 7.🔁 What number does this code show?
    let runs = [6, 5, 19];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  8. 8.🔁 What number does this code show?
    let steps = [18, 8, 9];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  9. 9.🔁 What does a loop do? (a) saves photos (b) deletes code (c) draws icons (d) repeats code
  10. 10.🔁 What number does this code show?
    let steps = [4, 3, 15, 14];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  11. 11.🔁 What number does this code show?
    let marks = [3, 3, 13, 9, 1];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  12. 12.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Arjun", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Riya
  13. 13.🔁 What number does this code show?
    let runs = [59, 45, 40];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  14. 14.🔁 What number does this code show?
    let steps = [17, 5, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  15. 15.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Aman (c) Hi, Zoya (d) Hi, Kabir
  16. 16.🔁 What number does this code show?
    let scores = [9, 1, 10, 14];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  17. 17.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Aman
  18. 18.🔁 What number does this code show?
    let scores = [8, 11, 16];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  19. 19.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 1 (d) 5
  20. 20.🔁 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
  21. 21.🔁 What number does this code show?
    let runs = [5, 3, 2, 19, 17];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  22. 22.🔁 What number does this code show?
    let steps = [28, 90, 45];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  23. 23.🔁 What number does this code show?
    let marks = [11, 3, 16, 15];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let steps = [14, 15, 15, 9];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  25. 25.🔁 What number does this code show?
    let scores = [19, 8, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  26. 26.🔁 What number does this code show?
    let steps = [10, 1, 10, 20];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  27. 27.🔁 What number does this code show?
    let runs = [9, 7, 18, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  28. 28.🔁 What number does this code show?
    let runs = [2, 20, 18, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  29. 29.🔁 What number does this code show?
    let scores = [12, 12, 10, 19, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  30. 30.🔁 What number does this code show?
    let steps = [15, 10, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  31. 31.🔁 What number does this code show?
    let scores = [23, 16, 19, 95, 72];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  32. 32.🔁 What number does this code show?
    let runs = [4, 4, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  33. 33.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Meera
  34. 34.🔁 What number does this code show?
    let marks = [10, 14, 20, 12];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  35. 35.🔁 What number does this code show?
    let scores = [47, 48, 18];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What number does this code show?
    let steps = [14, 98, 13, 73];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  37. 37.🔁 What number does this code show?
    let runs = [19, 6, 17, 18];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  38. 38.🔁 What number does this code show?
    let scores = [55, 11, 46];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  39. 39.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Riya
  40. 40.🔁 What number does this code show?
    let marks = [11, 2, 19];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);

Answer key

  1. Hi, Zoya
  2. 1
  3. 0, 1, 2
  4. Hi, Meera
  5. 2
  6. 19
  7. 19
  8. 18
  9. repeats code
  10. 36
  11. 29
  12. Hi, Zoya
  13. 0
  14. 28
  15. Hi, Aman
  16. 14
  17. Hi, Kabir
  18. 35
  19. 5
  20. less code to write
  21. 19
  22. 2
  23. 16
  24. 15
  25. 33
  26. 20
  27. 36
  28. 44
  29. 19
  30. 18
  31. 2
  32. 16
  33. Hi, Zoya
  34. 20
  35. 0
  36. 2
  37. 19
  38. 0
  39. Hi, Aman
  40. 19

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