Python lists | 4/100 Days of Python Algo trading

1. Python lists and arrays are similar but have a key difference. What is it?

Arrays must store elements of the same data type, lists can have mixed data types.

Lists are faster than arrays.

Arrays are created using the array module, lists are built-in.

Lists cannot be indexed, arrays can.

2. How are lists represented in Python's memory?

As a contiguous block of memory elements.

As a linked list (nodes with data and references to the next).

As a binary tree for fast searching.

As a hash table for efficient lookups.

3. Which of the following are characteristics of Python lists? (Choose all that apply)

Ordered

Immutable

Heterogeneous (can store different data types)

Fixed in size

4. What's the output of this code?
Python
my_list = [1, 2, "hello"]
print(my_list[1])

"hello"

An index error occurs

5. What's the difference between the append() and extend() methods for lists?

append() adds a single element, extend() adds elements from an iterable.

extend() adds an element at the beginning, append() adds to the end.

They are the same, but append() is faster.

insert() adds an element at a specific index, extend() adds to the end

6. What does my_list.insert(2, "new") do?

Adds "new" at the beginning of the list.

Inserts "new" at index 2 of my_list.

Replaces the item at index 2 with "new".

Returns the index where "new" is found in the list.

7. How can you delete the element at index 1 from a list named numbers?

del numbers[1]

numbers.delete(1)

numbers.remove_at(1)

numbers.pop(1)

8. What is the result of [1, 2, 3] * 2?

[1, 2, 3, 1, 2, 3]

[2, 4, 6]

[1, 1, 2, 2, 3, 3]

An error occurs

9. How do you check if the value 5 is present in a list named my_list?

if 5 in my_list:

if my_list.contains(5):

if my_list.find(5) != -1:

All of the above

10. What does the len() function do when used with a list?

Returns the length (number of elements) in the list.

Calculates the sum of the list elements.

Sorts the list in ascending order.

Finds the index of the first occurrence of an element.

11. What does the my_list.sort() method do?

Creates a new sorted copy of my_list.

Sorts my_list in-place (modifies it directly).

Reverses the order of elements in my_list.

Returns the maximum element in my_list.

12. How would you find the minimum value in a list called numbers?

min_value = numbers.min()

min_value = min(numbers)

min_value = numbers.minimum()

You would need to write a loop to find the minimum.

13. What does the list.reverse() method do?

Sorts the list in descending order.

Removes the last element of the list.

Reverses the order of elements in-place.

Creates a new list with elements in reverse order.

14. What's a concise way to create a list of squares of numbers 1 to 10?

squares = [x for x in range(1, 11)]

squares = [x * x for x in range(1, 11)]

squares = [x ** 2 for x in range(1, 11)]

squares = list.square([1, 2, 3, ..., 10])

15. How would you iterate through a list named colors and print both the index and value of each element?

for color in colors: print(color)

for i in len(colors): print(i, colors[i])

for index, color in enumerate(colors): print(index, color)

for i in colors: print(colors.index(i), i)

16. Consider these lists: names = ["Alice", "Bob"] and ages = [25, 30]. What's the output of list(zip(names, ages))?

[("Alice", 25), ("Bob", 30)]

["Alice", "Bob", 25, 30]

{"Alice": 25, "Bob": 30}

An error occurs

17. List as heterogeneous containers: Which code demonstrates that Python lists can store different data types?

my_list = [10, 20, 30]

my_list = [True, False, True]

my_list = [10, "hello", 3.14]

my_list = [] (an empty list)

18. What is a potential disadvantage of using Python lists?

They are difficult to create.

You cannot access elements by index.

They can be inefficient for frequent insertions/deletions at the beginning.

They cannot store different data types in the same list.

19. For scenarios focusing heavily on search operations, what might be a better alternative to a Python list?

A Python tuple

A Python dictionary

A Python set

None of the above, lists are optimal for search

20. In which situation might using a NumPy array be more advantageous than a Python list?

Storing names and email addresses of users

Performing large-scale numerical computations

Representing a simple deck of playing cards

All of the above

Congratulations on reaching this stage!