[Python] How to standardize feature with 1,000+ unique string values using pandas? [closed]

I have cars dataset, where it has feature name 'transmission', this feature has 1,292 unique values. Because it is string object, how to standardize this feature?

I tried to extract every token from string of transmission feature and make single column for every different inner category, than I tried to standardize that all inner category but at the end I have no result.

Continue reading...