Why does IDLE add a newline after my code?

Question

On my saving a .py file, IDLE (Python 3.9 x64) will add a newline after the code itself. It is setting off my OCD while making me curious. For instance, take this entirely original last line of a program while coding:

print("Hello, world!")

Yet, when saved, it becomes:

print("Hello, world!")
# ghost line!

What is the significance of that extra line—can I turn it off?

This does not seems tobe a real problem, is it ? Could you explain why it is a problem in your case ? In any case you could try another IDE / editor if you like. — Malo, Nov 27 '20 at 19:30
https://stackoverflow.com/questions/729692/why-should-text-files-end-with-a-newline — , Nov 27 '20 at 19:33
You are not seeing a new line, Just space for the next line. Normally every line in a text ends in a "newline" character. Not having the newline character can be problematic with certain scanning methods, or for, say, back to back file copies. — RufusVS, Nov 28 '20 at 16:09

score 1 · Answer 1 · answered Nov 27 '20 at 19:30

1

It is the best practice of Python to have an extra line at the end of the code. If you explicitly go and delete the last line, then it won't be there. But, my suggestion would be to keep it. It's always better to follow best practices.

answered Nov 27 '20 at 19:30

Richa Bhuwania

180
10

More exactly, it is good to complete the last line with a newline character. This does not make an extra line. When displayed, the cursor will be at left margin, ready to begin a new line. – Terry Jan Reedy Nov 28 '20 at 14:08
Is this "best practice" actually documented anywhere? – snakecharmerb Nov 28 '20 at 14:30
Could you show some references for this? I ask as, usually, the community has notes—if not documentation—on style guidelines like these. – niamulbengali Nov 28 '20 at 19:39
As far as Find goes, the newline at the end is not explicitly brought up in the PEP-8 style guide. – niamulbengali Nov 28 '20 at 20:11

score 1 · Accepted Answer · answered Nov 28 '20 at 14:25

IDLE has made sure that a file being saved ends with a newline ('\n') since the first commit in 2000. I believe that at one time the Python compiler required that every line, including the last, be complete, ending with a newline. It may be more lax now, under some circumstances, but I am not sure. There may be other things one does with a file that could require the proper ending.

Ghosts do not exist, and neither does the ghost line. A line of 0 characters is not really a line. The cursor at the left margin after the last line is ready to start a new line.

Thanks! Please give some examples of what you mean by "There may be other things one does with a file that could require the proper ending." — niamulbengali, Nov 28 '20 at 19:41

Why does IDLE add a newline after my code?

2 Answers2