9.Pandas怎样实现DataFrame的Merge
Pandas的Merge相当于sql的join,将不同的表关联在一个表
读取电影数据,sep为分割符
df_ratings=pd.read_csv(r'...\datas\movielens-1m\ratings.dat',sep='::',engine='python',names='UserID::MovieID::Rating::Timestamp'.split(':😂)
df_users=pd.read_csv(r'...\datas\movielens-1m\users.dat',sep='::',engine='python',names='UserID::Gender::Age::Occupation::Zip-code'.split(':😂)
取df_ratings,df_users两张DataFrame,其中左边df_ratings以UserID,右边的df_users以其UserID,合并方式为Inner进行merge
df_ratings_users_movie=pd.merge(df_ratings,df_users,left_on='UserID',right_on='UserID',how='inner')
注意合并后,其没有的值则默认填充为NaN