Python Tuples and Lists Quiz

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Questions and Answers

What characteristic of tuples most directly enables copy efficiency through aliasing?

Being immutable. (correct)

The ability to contain different types of elements.

The support for indexing and slicing.

The capability to be nested to multiple levels.

Which operation, when applied to a tuple, demonstrates a pass-by-value behavior rather than pass-by-reference?

Indexing elements within a tuple using square brackets `[]`.

Concatenating two tuples using the `+` operator.

Passing a tuple as an argument to a function. (correct)

Repeating a tuple using the `*` operator.

Considering the properties of tuples, which scenario benefits most directly from the fact that tuples do not require synchronization in concurrent code?

Creating a tuple with nested elements.

Iterating over the elements of a tuple in a loop.

Accessing elements of a tuple in a single-threaded application.

Sharing a tuple among multiple threads in a multithreaded application. (correct)

What does interning an immutable tuple achieve primarily?

Reduced memory footprint by storing only one copy of each unique tuple value. (A) Signup and view all the answers

What is the primary purpose of the parentheses `()` when creating a tuple in Python?

To explicitly define the scope and grouping of the elements within the tuple. (A) Signup and view all the answers

Which method correctly initializes an empty list in Python?

L = list() (D) Signup and view all the answers

What will be the output of the following Python code: `List = [x for x in range(20) if x % 3 == 0]`?

[0, 3, 6, 9, 12, 15, 18] (A) Signup and view all the answers

Which of the following is an incorrect method to create a list?

List = (1, 2, 3) (A) Signup and view all the answers

What is the data type of list returned by the expression `list()`?

<code>list</code> (C) Signup and view all the answers

Given the code `L = list(x*2 for x in range(5))`, what will be the value of `L`?

[0, 2, 4, 6, 8] (D) Signup and view all the answers

What is the primary difference between `List = [expression, ...]` and `List = [expression for variable in sequence]`?

The second one allows conditional evaluation of expressions based on the sequence. (A) Signup and view all the answers

If you want to perform some action on each element of the list, which option is the most suitable and readable?

Using list comprehension with <code>for</code> loop (A) Signup and view all the answers

What is the purpose of using `expression for variable in sequence` within square brackets?

To construct a list through list comprehension (D) Signup and view all the answers

What is the primary difference between using a `for` loop directly on a list versus using `for i in range(len(list))` when iterating in Python?

<code>for i in range(len(list))</code> allows direct access to element indices, enabling element updates or deletions, while <code>for x in list</code> is primarily for read-only access of elements. (A) Signup and view all the answers

When using the `del` statement on a list in Python, what is its primary function?

It removes an item from the list at a specific index. (B) Signup and view all the answers

Given `numbers = [50, 60, 70, 80]`, what will `print(numbers)` output after executing `del numbers[1:2]`?

[50, 70, 80] (B) Signup and view all the answers

What is the result of the operation `list = list[2:]` on a list?

It removes the first two items of the list. (A) Signup and view all the answers

How would you remove the elements at index 1 and 2 (inclusive) from a list called `my_list`?

Both B and C (A) Signup and view all the answers

What will be the output of the following code?

list1 = ['red', 'green', 5681, 2000]
del list1[2]
print(list1)

['red', 'green', 2000] (B) Signup and view all the answers

What is the correct way to iterate over a list of numbers and multiply each element by 2, updating the original list in place?

for i in range(len(numbers)): numbers[i] = numbers[i] * 2 (D) Signup and view all the answers

If `my_list = [10, 20, 30, 40, 50]`, what will `my_list` be after executing `my_list = my_list[3:]`?

[40, 50] (A) Signup and view all the answers

What is the primary difference between using the `append()` method within a loop and list comprehension for list concatenation in Python?

List comprehension provides a more readable and concise way to concatenate, while <code>append()</code> requires explicit looping. (C) Signup and view all the answers

If `list1 = [1, 2, [3, 4]]` and `list2 = [5, 6]`, what would be the output of `result = [j for i in [list1, list2] for j in i]`?

[1, 2, [3, 4], 5, 6] (D) Signup and view all the answers

Which of the following scenarios would be most suitable in Python lists when prioritizing code readability and conciseness?

Implementing list comprehension for simple, unconditional list concatenation. (A) Signup and view all the answers

Given `list1 = [1, 2, 3]` and `list2 = ['a', 'b']`, what is the most efficient way to combine them into `['a', 'b', 1, 2, 3]`?

<code>list2.extend(list1)</code> followed by <code>list2.reverse()</code> (A) Signup and view all the answers

What is the key distinction regarding memory usage between list comprehension and using the `extend()` method for concatenation, especially when dealing with very large lists?

List comprehension may temporarily require more memory due to the creation of a new list, while <code>extend()</code> modifies the list in place. (D) Signup and view all the answers

When concatenating numerous lists, what performance implications should be considered when choosing between repeated `append()` calls within a loop and the `extend()` method?

The <code>extend()</code> method has a lower time complexity due to its ability to add multiple elements at once, making it more efficient for concatenating numerous lists. (D) Signup and view all the answers

How does the `extend()` method handle the concatenation of a list with a string?

It iterates through the string, adding each character as a separate element to the list. (A) Signup and view all the answers

What would be the result if you tried to concatenate a dictionary to a list using the `extend()` method in Python, i.e., `list1.extend(dict1)`?

It would add the keys of the dictionary as individual elements to the list. (C) Signup and view all the answers

What should you specify to access a file located at 'c:/sample/readme.txt' in your code?

The absolute path to the file (A) Signup and view all the answers

Which mode would you use to ensure that you are only writing to a text file and not reading from it?

'w' (A) Signup and view all the answers

What is the return type of the readlines() method when reading from a text file?

A list of strings, each representing a line (B) Signup and view all the answers

If you want to read the entire content of a small file into a single variable, which method should you use?

read() (D) Signup and view all the answers

Which option correctly indicates that you intend to add new content to a file without deleting its current content?

'a' (D) Signup and view all the answers

What will happen if you open a text file using the 'w' mode that already exists?

The existing contents will be erased (D) Signup and view all the answers

When would you prefer to use the readline() method over the read() method?

When you want to process lines one at a time (C) Signup and view all the answers

What is the correct assignment to open the file 'the-zen-of-python.txt' in read mode?

f = open('the-zen-of-python.txt', 'r') (A) Signup and view all the answers

What is the result of the statement dic.pop('first') when applied to the dictionary dic = {'first': 1, 'second': 2, 'third': 3, 'fourth': 4}?

{'second': 2, 'third': 3, 'fourth': 4} (B) Signup and view all the answers

Which function would you use to retrieve only the keys from the dictionary dic = {'first': 1, 'second': 2, 'third': 3}?

dic.keys() (B) Signup and view all the answers

What is the output of dic.copy() if dic = {'first': 1, 'second': 2}?

{'first': 1, 'second': 2} (C) Signup and view all the answers

Which function removes all elements from a dictionary?

dic.clear() (B) Signup and view all the answers

What does the function dic.popitem() do?

Removes the last inserted key-value pair (D) Signup and view all the answers

If dic = {'first': 1, 'second': 2}, what value is returned by dic.get('third')?

None (D) Signup and view all the answers

Which of the following statements is true regarding tuples in Python compared to lists?

Tuples are immutable while lists are mutable (B) Signup and view all the answers

Which of these returns a list of all values in the dictionary dic = {'a': 1, 'b': 2, 'c': 3}?

dic.values() (C) Signup and view all the answers

Flashcards

List Creation

Lists can be created using square brackets with expressions.

List Syntax

List can be defined as List = [expression, …].