Update pandas inplace operation

[Etrama]

To make sure the code is future proof (pandas 3 proof), all the pandas operations that mention"inplace=True" need to be updated. At the time I checked, this was 53 results in 20 files:

No promises, but I might make a pull request that fixes this.

If you need more evidence: stackoverflow post.

[AllenDowney]

Thanks for bringing this to my attention, and thanks for the offer to make a PR, but I'll ask you to hold off.

First, a lot of the code in this repo gets generated from other code, so you don't want to modify the ones that get generated.

Second, I am unsure whether I will future-proof this code or not -- I might just pin it to Pandas < 3.0.

Thinking...

[Etrama]

Food for thought-
Cons:

• Extra effort: There are also some explanations in the book's text that would need to be updated if the "inplace" operations were updated.
  
  

Pros:

• Good python and pandas habits inculcated in people who read the book. If newbies aren't exposed to "inplace", I daresay they will stick to what they know. However, one could also argue that people motivated enough would find this out themselves.

I'll leave the final decision to you.