ML studying

1) crosstab - To make frequency tableimport pandas as pd df = pd.read_csv('iris.csv') pd.crosstab(df.loc[:10, 'Sepal.Width'], df.loc[:10, 'Petal.Width'])2) isna() isna() is the same with isnull() In reverse, notna() is the same with notnull() 3) fillna() To handle nan value easily, fillna() is used.Signature: df.fillna(value=None, method=None, axis=None, inplace=False, limit=None, downcast=None,..

1) iloc vs loc iloc is to use integer index in dataframe. loc is to use category name in dataframe.import pandas as pd df = pd.read_csv('iris.csv') %To read csv file, use pandas.read_csv df.head(2)df_sub1 = df.loc[:, ['petal.length', 'petal.width', 'variety']] print(df_sub1.head(2)) df_sub2 = df.iloc[:, 2:] print(df_sub2.head(2)) 2) unique It is used to see what categories are included in specif..