DataFrame operations didn't change orginal

[HoldYourBreath]

It would help to have the whole error message, so we can see where this is happening.

I believe the issue is the way Python handles variable names. a=b does not copy b to a, rather it creates variable a that points to the same value that b does. Changes to that value mean that a and b are both changed. Usually. Unless the operation results in a reassignment that separates the two.

Sounds confusing, would refer you to a Pycon talk by Ned Batchelder PyCon 2015

edited orginal massage and add whole error massage

i understand change issue. but in my example it didnt change. i trace step by step DF.shape and after "line 22" it change to its orginal value so the alterations that i make is gone.