When a series has dtype="object", series.iloc[0] = {} converts the series element to a pandas Series, instead of storing the dictionary:

import pandas s = pandas.Series(0, dtype="object") s[0] = {} assert s[0] == {} # passes s.iloc[0] = {} assert s[0] == {} # fails

I was surprised by this behavior, because I expected that dtype="object" would let me store the actual dictionary inside the series.

If this is expected behavior, I'd love to know if there's a recommended way to store dictionary values inside of a object-dtype series without it being converted.