Cron Merdek questions

• Merging pandas categorical Series with renaming
• How to keep track of dependencies with immutable design?
• Select numpy array of different shape by index and write it back
• Inplace transformation pandas with groupby
• remove_if last character from a string
• How to get reference to inserted object from std::map::emplace()?
• filter rows in data.table with `by`

Cron Merdek answers