POC Data Structures & File Handling

Question 1

Which of the following is a mutable data type in Python?

Accepted Answer

List

Answer

A mutable data type is one whose value can be changed after it has been created. In Python, lists are mutable, meaning you can add, remove, or modify elements within a list. Tuples, strings, and integers are immutable; once created, their values cannot be altered without creating a new object.

Question 2

How do you add an item to a list in Python?

Accepted Answer

list.append(item)

Answer

The `append()` method is the standard way to add an item to the end of a list in Python. It modifies the list in-place by adding the new element as the last item. Other methods like `insert()` allow adding at a specific index, but `append()` is specifically for adding to the end of the list efficiently.

Question 3

Which data structure uses key-value pairs?

Accepted Answer

Dictionary

Answer

A dictionary in Python is an unordered collection of data values, used to store data in key-value pairs. Each key must be unique and immutable, while values can be of any data type and can be duplicated. Dictionaries are highly efficient for retrieving values based on their associated keys, making them ideal for mapping data.

Question 4

What is the correct way to open a file for reading?

Accepted Answer

open('file.txt')

Answer

When using the `open()` function in Python, if no mode is specified, it defaults to `'r'`, which stands for read mode. Therefore, `open('file.txt')` is the correct and most common way to open a file for reading its contents. Other modes like `'w'` (write), `'x'` (exclusive creation), and `'a'` (append) serve different purposes.

Question 5

Which method is used to read the entire content of a file?

Accepted Answer

read()

Answer

The `read()` method in Python is specifically designed to read the entire content of a file as a single string. In contrast, `readline()` reads only one line at a time. The other options, `readall()` and `fetch()`, are not standard Python file methods for this purpose.

(POC) Python Online Certification Practice Test

(POC) Python Online Certification Practice Test

POC Data Structures & File Handling