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App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 532 · 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.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the biggest item (d) the first item
  2. 2.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it is slower (c) less code to write (d) it uses more lines
  3. 3.🔁 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, Meera (b) Hi, Aman (c) Hi, Zoya (d) Hi, Kabir
  4. 4.🔁 What number does this code show?
    let runs = [8, 14, 17];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  5. 5.🔁 What number does this code show?
    let runs = [11, 8, 5];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  6. 6.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Meera (c) Hi, Kabir (d) Hi, Arjun
  7. 7.🔁 What number does this code show?
    let runs = [18, 19, 20];
    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, 12, 2, 5];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  9. 9.🔁 What number does this code show?
    let runs = [29, 61, 22, 76];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  10. 10.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Riya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Meera (d) Hi, Riya
  11. 11.🔁 What number does this code show?
    let steps = [78, 21, 62, 28, 18];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
  13. 13.🔁 What number does this code show?
    let scores = [7, 15, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  14. 14.🔁 What number does this code show?
    let marks = [17, 9, 10, 5, 7];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  15. 15.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun (d) Hi, Kabir
  16. 16.🔁 What number does this code show?
    let marks = [2, 5, 20];
    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 = [48, 33, 94];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Meera
  19. 19.🔁 What number does this code show?
    let runs = [4, 14, 10, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  20. 20.🔁 What number does this code show?
    let marks = [45, 94, 20];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What number does this code show?
    let scores = [74, 11, 52];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  22. 22.🔁 What number does this code show?
    let runs = [3, 14, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  23. 23.🔁 What number does this code show?
    let steps = [1, 3, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  24. 24.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Aman (b) Hi, Kabir (c) Hi, Zoya
  25. 25.🔁 What does a loop do? (a) deletes code (b) repeats code (c) saves photos (d) draws icons
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Zoya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Kabir (d) Hi, Riya
  27. 27.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Zoya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Riya (d) Hi, Arjun
  28. 28.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Aman (c) Hi, Zoya
  29. 29.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Zoya (c) Hi, Arjun
  30. 30.🔁 What number does this code show?
    let steps = [11, 16, 2, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  31. 31.🔁 What number does this code show?
    let marks = [10, 20, 14, 5];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  32. 32.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya (d) Hi, Meera
  33. 33.🔁 What number does this code show?
    let marks = [5, 6, 7, 13];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  34. 34.🔁 What number does this code show?
    let runs = [1, 1, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  35. 35.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya (d) Hi, Kabir
  36. 36.🔁 What number does this code show?
    let runs = [6, 5, 14, 19];
    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 = ["Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya
  38. 38.🔁 What number does this code show?
    let runs = [18, 10, 13];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  39. 39.🔁 What number does this code show?
    let scores = [58, 72, 52, 21, 55];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  40. 40.🔁 What number does this code show?
    let runs = [96, 19, 10];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);

Answer key

  1. how many items it has
  2. less code to write
  3. Hi, Kabir
  4. 17
  5. 24
  6. Hi, Arjun
  7. 20
  8. 45
  9. 2
  10. Hi, Meera
  11. 2
  12. 5
  13. 15
  14. 48
  15. Hi, Zoya
  16. 20
  17. 1
  18. Hi, Kabir
  19. 14
  20. 1
  21. 2
  22. 14
  23. 6
  24. Hi, Kabir
  25. repeats code
  26. Hi, Kabir
  27. Hi, Kabir
  28. Hi, Zoya
  29. Hi, Meera
  30. 31
  31. 49
  32. Hi, Riya
  33. 31
  34. 15
  35. Hi, Kabir
  36. 19
  37. Hi, Aman
  38. 18
  39. 1
  40. 1

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