File Handling In Python

In Python, to implement a Double-Ended Queue (Deque), we need to import the collections module. The collections module provides a range of specialized container data types in addition to Python's built-in containers such as lists, dictionaries, and tuples. One of these is deque (double-ended queue), which supports thread-safe, memory-efficient appends and pops from either side of the deque with approximately the same O(1) performance in either direction.
To use a deque, you can import and initialize it as follows:

from collections import deque
dq=deque()

With deque, you can perform operations such as append() and appendleft() for adding elements, along with pop() and popleft() for removing them from either end.

In programming, to manipulate file pointers in languages such as Python, the seek() method is often used to move the file pointer to a specific position within a file. The syntax of seek() includes parameters to specify the number of characters to move and the reference position from which to start moving.
The method call fp.seek(n, r) is designed to move the file pointer by n characters relative to a position r. Here, r can take certain values, indicating the starting point:

• 0 - Beginning of the file
• 1 - Current position
• 2 - End of the file

Moving the file pointer is a common operation in file handling, allowing reading and writing from any location within the file. Among the provided options, only fp.seek(n, r) correctly specifies the seek method with both n and r arguments, making it the correct choice for moving the file pointer to the nth character with respect to the r position.

To correctly match the methods and their functionalities from List-I and List-II, let's analyze each:

• (A) readline(): This method reads a single line from a file. Thus, it matches with (II).
• (B) writelines(): This method writes a sequence of strings to a file. Thus, it matches with (I).
• (C) seek(): This method moves the file pointer to a specified position within the file. Thus, it matches with (IV).
• (D) flush(): This method forces any buffered output to be written to the file. Thus, it matches with (III).

The correct answer is: (A) - (II), (B) - (I), (C) - (IV), (D) - (III)