Python Exception Handling Quiz

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Questions and Answers

When an exception occurs within a `try` block, what is the order in which the `except` blocks are evaluated?

The `except` blocks are evaluated sequentially from top to bottom, and the first matching exception type is executed. (correct)

The `except` blocks are evaluated in a random order until a matching exception type is found.

All `except` blocks are executed regardless of the exception type.

The `except` blocks are evaluated based on their proximity to the line of code that raised the exception.

Which file object attribute returns a Boolean value indicating whether the file is connected to a tty(-like) device?

`file.mode`

`file.name`

`file.closed`

`file.isatty()` (correct)

If a file is opened in `'w'` mode and a `FileNotFoundError` is raised, what is the likely cause?

The file already exists, and the operating system prevents it from being overwritten.

The user lacks the necessary permissions to write to the file.

Python's file I/O library is corrupted.

The directory specified in the file path does not exist. (correct)

What happens if an exception is raised inside the `finally` block of a `try...except...finally` statement?

The exception propagates up the call stack, replacing any previously caught exception. (A) Signup and view all the answers

Which statement about user-defined exceptions in Python is most accurate?

User-defined exceptions can be used to represent errors or exceptional conditions specific to an application or library. (D) Signup and view all the answers

Which action is permissible on a list but not on a tuple in Python?

Modifying an element at a specific index. (A) Signup and view all the answers

What is a key characteristic that distinguishes dictionaries from tuples in Python?

Dictionaries store key-value pairs, while tuples store ordered elements. (D) Signup and view all the answers

If a function needs to return multiple distinct values, what data structure is best suited for this purpose, given the information?

A tuple, due to its immutability and ability to group related values. (B) Signup and view all the answers

In the context of dictionaries, what is a key property that all keys must possess?

Keys must be unique within the dictionary. (B) Signup and view all the answers

When considering the use of tuples versus lists in Python, which scenario would most strongly favor the use of a tuple?

Representing the coordinates of a geographical location (latitude, longitude) which should not be altered. (D) Signup and view all the answers

You have a dictionary `my_dict = {'a': 1, 'b': 2, 'c': 3}`. Which operation is the most efficient way to remove the key 'b' and its corresponding value from the dictionary?

<code>del my_dict['b']</code> (B) Signup and view all the answers

How do you access keys within a dictionary?

By directly calling the key within square brackets <code>[]</code> (C) Signup and view all the answers

Considering efficiency and memory usage, which data type is preferable for storing a fixed collection of heterogeneous data (e.g., name, age, city) that will not be modified after creation?

Tuple (C) Signup and view all the answers

What is the primary difference between using `readline()` and `readlines()` when reading a file in Python?

<code>readline()</code> reads one line at a time, returning a string, while <code>readlines()</code> reads all lines, returning a list of strings. (A) Signup and view all the answers

When using the `open()` function in Python to read a file, what is the significance of the 'mode' parameter?

It indicates the purpose for which the file is opened (e.g., reading, writing, appending). (A) Signup and view all the answers

If a Python script and a text file (`data.txt`) are located in the same directory, how should the path be specified when opening the file using the `open()` function?

Only the file name (<code>data.txt</code>) needs to be specified. (C) Signup and view all the answers

What happens if you attempt to use `readline()` on a file that has already been fully read?

It returns an empty string (<code>''</code>). (D) Signup and view all the answers

Which of the following is the correct way to ensure that a file is properly closed after reading, even if an exception occurs?

Using the <code>with open()</code> statement, which automatically closes the file. (B) Signup and view all the answers

What is the potential consequence of not closing a file after reading it in a Python script?

The file will remain locked, preventing other processes from accessing it. (A) Signup and view all the answers

When specifying a file path in the `open()` function in Python, which type of slash should be used, regardless of the operating system?

Forward-slash ('/') (A) Signup and view all the answers

Which method reads all the lines of a file and returns them as a list of strings, including the newline character at the end of each line?

<code>readlines()</code> (B) Signup and view all the answers

What is the key distinction between tuple packing and unpacking in Python?

Packing assigns multiple values to a single tuple, while unpacking assigns tuple values to individual variables. (D) Signup and view all the answers

Given `tuple1 = (1, [2, 3], 'a')`, which operation would result in an error?

<code>tuple1[0] = 5</code> (B) Signup and view all the answers

What is the outcome of attempting to modify a tuple directly, and why does this occur?

A TypeError exception is raised due to the immutability of tuples. (A) Signup and view all the answers

Considering `t = (1, 2, [3, 4])`, what is the effect of `t[2].append(5)`?

It modifies the list within the tuple, resulting in <code>(1, 2, [3, 4, 5])</code>. (B) Signup and view all the answers

If `tuple1 = (1, 2, 3)` and `tuple2 = ('a', 'b', 'c')`, what would `tuple1 * len(tuple2)` evaluate to?

<code>((1, 2, 3), (1, 2, 3), (1, 2, 3))</code> (A) Signup and view all the answers

Given `my_tuple = (1, 2, 3, 4, 5)`, what will `my_tuple[::-2]` return?

<code>(5, 3, 1)</code> (A) Signup and view all the answers

What is the primary advantage of using tuples over lists in Python?

Tuples consume less memory and offer better performance when data should not be modified. (A) Signup and view all the answers

If `tup = (1, 2, 3)`, what is the difference between `tup * 3` and `(tup) * 3`?

There is no difference; both produce the same result. (D) Signup and view all the answers

In Python exception handling, what is the primary purpose of the `else` block within a `try-except` structure?

To execute code only when no exceptions were raised in the <code>try</code> block. (C) Signup and view all the answers

Which block in a `try-except` construct is guaranteed to execute, irrespective of whether an exception is raised or not?

The <code>finally</code> block. (C) Signup and view all the answers

When handling exceptions in Python, which of the following is the correct way to catch multiple specific exception types with a single `except` block?

<code>except (ExceptionType1, ExceptionType2):</code> (D) Signup and view all the answers

What is the function of arguments passed to exceptions in Python?

To provide additional, context-specific information about the error. (B) Signup and view all the answers

In the context of exception handling, what is the IOError exception typically used to catch?

Errors that occur when dealing with input/output operations, such as file handling. (A) Signup and view all the answers

If a `try` block raises an exception that is not caught by any of the specified `except` blocks, what happens?

The program searches for an <code>except</code> block in the calling function or global scope. (A) Signup and view all the answers

When an exception is raised within the `try` block and caught by an `except` block, which block is executed next?

The first <code>except</code> block that handles the exception type. (A) Signup and view all the answers

What is the purpose of using arguments with built-in exceptions?

To provide more details about the error encountered. (A) Signup and view all the answers

What is a primary limitation of using lists when dealing with very large datasets?

Lists load all elements into memory simultaneously, potentially consuming excessive resources. (B) Signup and view all the answers

In Python, what does it mean for a list to be 'ordered'?

The elements have a specific sequence, where each element has a defined position. (D) Signup and view all the answers

If a list contains duplicate values, how are these values handled with respect to indexing?

Each occurrence maintains a discrete place in the sequence and is indexed accordingly. (A) Signup and view all the answers

What is the index of the first element in a Python list?

0 (D) Signup and view all the answers

Which of the following scenarios would be best suited for using a list data structure?

Storing an ordered sequence of items where the order of insertion is important. (B) Signup and view all the answers

What potential issue should be considered when appending one list to another, particularly with large lists?

Appending can increase memory usage significantly, especially if both lists are large. (C) Signup and view all the answers

Given two lists, what is the most efficient way to identify and extract common items between them, while preserving the original order?

Use list comprehension with a conditional statement to check for membership of elements from the first list in the second list. (A) Signup and view all the answers

What are the implications of using list comprehensions on very large lists, compared to traditional `for` loops?

List comprehensions may consume more memory initially but can offer faster execution for certain operations. (D) Signup and view all the answers

Flashcards

Tuple

An ordered collection of elements in Python that cannot be modified.

Difference between List and Tuple

A list can be changed, while a tuple cannot after creation.