https://pandas.pydata.org/docs/user_guide/index.html https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.value_counts.html https://pandas.pydata.org/docs/getting_started/intro_tutorials/06_calculate_statistics.html https://pandas.pydata.org/docs/getting_started/intro_tutorials/09_timeseries.html https://www.datacamp.com/community/blog/python-pandas-cheat-sheet?utm_source=adwords_ppc&utm_campaignid=12492439802&utm_adgroupid=122563403481&utm_device=c&utm_keyword=extract%20columns%20pandas&utm_matchtype=b&utm_network=g&utm_adpostion=&utm_creative=504158804614&utm_targetid=aud-743261776262:kwd-614516587576&utm_loc_interest_ms=&utm_loc_physical_ms=1005394&gclid=Cj0KCQjw1PSDBhDbARIsAPeTqrfoNwA3ANYBBsaMaQ8L8knsKcDdj5Vu2-LTs7iaOL3m-ysY0H4YBzMaAjKyEALw_wcB https://re-thought.com/pandas-value_counts/