How can I efficiently jump to a specific line in a large text file?

Optimizing Line Jumping in Large Text Files: An Alternative Approach

When processing massive text files with lines of varying lengths, it's often inefficient to sequentially read each line to reach a specific line number. The code sample provided in the question illustrates this approach, requiring a potentially slow iteration through the entire file. However, there is an alternative method that optimizes line jumping by leveraging a calculated offset list.

Offset-Based Line Jumping

To overcome this challenge, a more efficient approach involves reading the file once to create a list of line offsets. Each offset marks the starting position of a particular line. By storing these offsets, you can directly jump to a desired line without processing the preceding ones.

Here's an improved code snippet:

<code class="python"># Read the file and build the line offset list
line_offset = []
offset = 0
with open(filename, "rb", 0) as file:
    for line in file:
        line_offset.append(offset)
        offset += len(line)

# Jump to a specific line (line 141978 in this example)
file.seek(line_offset[141977])  # Adjust the index as lines are zero-indexed

# Process the target line as desired
DoSomethingWithThisLine(line)</code>

By utilizing the line offset list, you can skip to the target line directly, significantly reducing processing time and improving efficiency.

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