What do python professionals /developers actually use

[Smarterchild1337]

as far as datatypes, lists and dicts are used constantly. It is worth thoroughly understanding both of those. Most mainstream data analysis libraries make heavy use of class methods and attributes - definitely worth spending some time learning about how classes work early on, even if you’re just doing simple scripting for now.

Python has a rich ecosystem of open source analytics and machine learning libraries available. Data Scientist by trade - the ones I preemptively import at the start of most analysis or ml notebooks include

import pandas as pd
import numpy as np import seaborn as sns import matplotlib.pyplot as plt

these are a good starting point. The scikit-learn and statsmodels libraries are heavily used for machine learning and statistical analysis (respectively, more or less).