I agree that if scaling is used on the training data, it should also be used on the test data.
However, from what I see in the pcr documentation there is not scale option in the function. This seems to be confirmed by running the code from the example in the documentation:
Extra-random Trees needs a target variable, so Isolation Forest generates a random target (sklearn, solitude). At prediction time, no y values are used, and the ExtraTrees doesn't actually make a prediction; instead, the samples are propagated to the leaves and the depth is extracted (sklearn).
As for the tree-building process, sklearn at least doesn't make ...
To add onto @Nicholas James Bailey's answer:
tidytext provides functionality for two different main operations: text mining and text modeling.
I think the text mining part of it where we tokenize, tidy and prep text data is a bit more unique. As pointed out there are several model alternatives for text data, some of which are arguably better.
In terms of ...