My questions:

1. Does Python's linecache read the entire file into memory?

2. Have I found (yet another) situation in which AI generates an answer that is at least unreliable and at worst false?

The background story.

I want to read a few lines in a text file in Python. I might have tens of millions of lines of which I only need at most 10. I know the line number at which I must start. Call this line n[0]. Line n[0] contains data that tells me what is the next line I need, hence n[1]. Line n[1] tells me what n[2] is and so forth. I know under what conditions I can terminate this chain.

Using duckduckgo I searched using the term "read at specific line in file in python". One possibilty offered was to use linecache.

1. From geeksforgeeks.

https://www.geeksforgeeks.org/python/how-to-read-specific-lines-from-a-file-in-python/

2. From an old SO posting.

https://stackoverflow.com/a/620397

From this SO posting one user gave the following comment:

I just checked the source code of this (linecache) module: the whole file is read in memory!

How to jump to a particular line in a huge text file?

3. My friendly AI assistant (duckduckgo) also suggested linecache. Here is a screen capture of part of its answer.

I repeat the yellow highlighted text:

The linecache module allows you to read a specific line from a file without loading the entire file into memory.

This directly contradicts the comment of the SO user.

The AI assistant provided two references:

https://pynative.com/python-read-specific-lines-from-a-file/

https://cs.stanford.edu/people/nick/py/python-file.html

As far as I can detect, neither of these references claim that linecache does not load the entire file into memory. In fact, the former states the opposite (albeit with a typo):

Note: The linache (sic) reads the whole file in memory.

Hence, my two questions above.