Pandas:当列值与另一个DF的列值匹配时,提取DF的行

Question

我有两个DF1和DF2,如下所述.两个数据帧的第一列"POS"可能匹配,但其他列将不同.我想比较两个数据帧的'POS'列,如果DF1的'POS'值在DF2'POS'列中,我想将该行存储在新的DF1数据帧中,并对DF2执行相同的操作.通过将POS保持为键并比较它们以获得相应的值,我可以轻松地使用字典.但字典不会接受重复的"POS"值,所以我想知道Pandas DF是否有解决方案.

df1 = 
   POS   id    freq
0 100 "idex" 3.0
1 102 "ter" 2.0
2 102 "pec" 4.0
3 103 "jek" 4.0
4 104 "jek" 4.0


df2 = 
   POS   id    freq
0 100 "treg" 3.0
1 102 "dfet" 2.2
2 102 "idet" 7.0
3 108 "jeik" 1.0
4 109 "jek" 4.0

Expected:
new_df1 = 
   POS   id    freq
0 100 "idex" 3.0
1 102 "ter" 2.0
2 102 "pec" 4.0


new_df2 = 
   POS   id    freq
0 100 "treg" 3.0
1 102 "dfet" 2.2
2 102 "idet" 7.0

Answer 1

您可以使用isin两个数据帧:

new_df1 = df1[df1.POS.isin(df2.POS)]

new_df2 = df2[df2.POS.isin(df1.POS)]

>>> new_df1
   POS    id  freq
0  100  idex   3.0
1  102   ter   2.0
2  102   pec   4.0
>>> new_df2
   POS    id  freq
0  100  treg   3.0
1  102  dfet   2.2
2  102  idet   7.0