1유형은 아래 세가지 함수를 꼭 마스터 하도록 하자 groupbysort_values()value_counts() import pandas as pdimport mathdf = pd.read_csv("data/employee_performance.csv")#print(df.head())#print(df.info())#print(df.isnull().sum())df['고객만족도'] = df['고객만족도'].fillna(df['고객만족도'].mean())df = df.dropna(subset=['근속연수'])#print(df.info())#print(df.isnull().sum())#a = df['고객만족도'].quantile(0.75)#a_trunc = math.trunc(a)#print(a_trunc)#..