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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 982 · 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", "Aman", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Zoya (c) Hi, Riya (d) Hi, Meera
  2. 2.🔁 What number does this code show?
    let steps = [13, 3, 13];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  3. 3.🔁 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
  4. 4.🔁 What number does this code show?
    let steps = [10, 14, 3, 7, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  5. 5.🔁 What number does this code show?
    let steps = [44, 46, 65];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  6. 6.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Kabir (d) Hi, Arjun
  7. 7.🔁 What number does this code show?
    let scores = [59, 14, 60, 22, 82];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  8. 8.🔁 What number does this code show?
    let scores = [16, 6, 3, 13];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  9. 9.🔁 What number does this code show?
    let runs = [63, 41, 12, 17];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  10. 10.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 5 (d) 6
  11. 11.🔁 What number does this code show?
    let steps = [5, 17, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  12. 12.🔁 What number does this code show?
    let scores = [12, 10, 1, 8, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  13. 13.🔁 What number does this code show?
    let scores = [27, 42, 62, 67, 28];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  14. 14.🔁 What number does this code show?
    let marks = [12, 15, 8];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  15. 15.🔁 What number does this code show?
    let runs = [15, 12, 5];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  16. 16.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Aman (c) Hi, Zoya (d) Hi, Meera
  17. 17.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Arjun
  18. 18.🔁 What number does this code show?
    let marks = [20, 14, 16, 17, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  19. 19.🔁 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, Kabir (b) Hi, Aman (c) Hi, Meera
  20. 20.🔁 What number does this code show?
    let runs = [4, 11, 3, 11, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  21. 21.🔁 What number does this code show?
    let steps = [13, 17, 9, 19, 5];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  22. 22.🔁 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, Kabir (b) Hi, Arjun (c) Hi, Riya (d) Hi, Aman
  23. 23.🔁 What number does this code show?
    let marks = [46, 35, 30];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  24. 24.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
  25. 25.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Kabir (c) Hi, Meera
  26. 26.🔁 What number does this code show?
    let steps = [7, 3, 9, 4, 17];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  27. 27.🔁 What number does this code show?
    let scores = [6, 9, 3, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  28. 28.🔁 What number does this code show?
    let steps = [19, 12, 6, 20];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  29. 29.🔁 What number does this code show?
    let scores = [8, 20, 9, 10, 16];
    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 = [86, 62, 13, 29, 29];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let steps = [14, 14, 40, 82];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  32. 32.🔁 What number does this code show?
    let marks = [83, 69, 44, 61, 48];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What number does this code show?
    let steps = [7, 18, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  34. 34.🔁 What does a loop do? (a) deletes code (b) saves photos (c) draws icons (d) repeats code
  35. 35.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the biggest item (d) the first item
  36. 36.🔁 What number does this code show?
    let steps = [47, 14, 43, 35, 52];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  37. 37.🔁 What number does this code show?
    let steps = [3, 12, 14, 4];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  38. 38.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 3 (c) 1, 2, 3 (d) 0, 1, 2
  39. 39.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman (d) Hi, Arjun
  40. 40.🔁 What number does this code show?
    let runs = [19, 16, 14];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);

Answer key

  1. Hi, Meera
  2. 13
  3. less code to write
  4. 40
  5. 3
  6. Hi, Riya
  7. 2
  8. 38
  9. 1
  10. 5
  11. 31
  12. 41
  13. 2
  14. 15
  15. 32
  16. Hi, Aman
  17. Hi, Kabir
  18. 81
  19. Hi, Meera
  20. 35
  21. 19
  22. Hi, Aman
  23. 0
  24. Hi, Arjun
  25. Hi, Kabir
  26. 40
  27. 26
  28. 57
  29. 63
  30. 2
  31. 1
  32. 3
  33. 19
  34. repeats code
  35. how many items it has
  36. 0
  37. 33
  38. 0, 1, 2
  39. Hi, Arjun
  40. 19

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