[PYTHON] One day the jupyter notebook suddenly stopped opening [memory error]

What happened

Detect the object with jupyter notebook by packing the kaggle kernel. Learn machine learning before going to bed. Memory error when waking up in the morning And when I try to open the notebook again, it's heavy. And can't open (memory error) (I forgot to take a photo)

Well, I wondered what happened, and when I tried to push to git for the time being, an error occurred. Reason ... 150MB. Eh! Not so much! I thought

Reason

I can't open jupyter, so I have to open .ipynb with vim. light And notice

2 million lines

If you take a look at ipynb, it's for debug

print(images)

The ones I have saved are displayed infinitely. 2 million lines

It doesn't bother me because it folds up in my notebook, but it seems like it happened because I record everything in memory. So I erase this 2 million lines with vim

2000000 dd

Then, if you adjust the key brackets etc., you can open it

in short

It may be dangerous to print too carelessly