feature request: efficient "random access" DataFrame creation
Currently, when trying to build a DataFrame in "random access" mode (adding rows \ columns dynamically) it's pretty slow, and the best practice is to build a python object (list of dicts, or something similar), and later convert it to a DataFrame

it would be convenient to have "DataFrame Builder" - an object that supports DataFrame indexing, but has a dictionary backend, which can later be converted to a regular data frame.

This is mainly syntactic sugar on top of current best practices, but it should make relevant code much clearer