[英]Join dataframes based on partial string-match between columns
我有一個 dataframe 我想比較它們是否存在於另一個 df 中。
after_h.sample(10, random_state=1)
movie year ratings
108 Mechanic: Resurrection 2016 4.0
206 Warcraft 2016 4.0
106 Max Steel 2016 3.5
107 Me Before You 2016 4.5
我想比較上述電影是否出現在另一個 df 中。
FILM Votes
0 Avengers: Age of Ultron (2015) 4170
1 Cinderella (2015) 950
2 Ant-Man (2015) 3000
3 Do You Believe? (2015) 350
4 Max Steel (2016) 560
我想要這樣的東西作為我的最終 output:
FILM votes
0 Max Steel 560
有兩種方式:
獲取部分匹配的行索引: FILM.startswith(title)
或FILM.contains(title)
。 兩者之一:
df1[ df1.movie.apply( lambda title: df2.FILM.str.startswith(title) ).any(1) ]
df1[ df1['movie'].apply(lambda title: df2['FILM'].str.contains(title)).any(1) ]
movie year ratings
106 Max Steel 2016 3.5
movie_title (year)
,則可以使用merge()
movie_title (year)
。.
# see code at bottom to recreate your dataframes
df2[['movie','year']] = df2.FILM.str.extract('([^\(]*) \(([0-9]*)\)')
# reorder columns and drop 'FILM' now we have its subfields 'movie','year'
df2 = df2[['movie','year','Votes']]
df2['year'] = df2['year'].astype(int)
df2.merge(df1)
movie year Votes ratings
0 Max Steel 2016 560 3.5
(感謝@user3483203 在這里和 Python 聊天室的幫助)
重新創建數據幀的代碼:
import pandas as pd
from pandas.compat import StringIO
dat1 = """movie year ratings
108 Mechanic: Resurrection 2016 4.0
206 Warcraft 2016 4.0
106 Max Steel 2016 3.5
107 Me Before You 2016 4.5"""
dat2 = """FILM Votes
0 Avengers: Age of Ultron (2015) 4170
1 Cinderella (2015) 950
2 Ant-Man (2015) 3000
3 Do You Believe? (2015) 350
4 Max Steel (2016) 560"""
df1 = pd.read_csv(StringIO(dat1), sep='\s{2,}', engine='python', index_col=0)
df2 = pd.read_csv(StringIO(dat2), sep='\s{2,}', engine='python')
給定輸入數據幀df1
和df2
,您可以通過pd.Series.isin
使用布爾索引。 要對齊電影字符串的格式,您需要先從df1
連接電影和年份:
s = df1['movie'] + ' (' + df1['year'].astype(str) + ')'
res = df2[df2['FILM'].isin(s)]
print(res)
FILM VOTES
4 Max Steel (2016) 560
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