Check data frame(panda as pd) column value between two file then summation the value if match

Question

I have made two data frame

df1=pd.read_csv()
df2=pd.read_csv()

df1

**A     B   C**

  Jhon  3   4

  David 3   6

df2

**A     B   C**

  leu   3   4

  Jhon  7   6
  David 6   8

I want to do like, if the name column(A) of df1 is match with name column(A) of df2, then the matched row of df2 will provide summation of total number of column B of df2. finally my result will be like :

total_matchedValueOf_B= 7+6=13.

Answer 1

You could use isin() method and boolean indexing:

df2.loc[df2['A'].isin(df1['A']), 'B'].sum()

Answer 2

Use df.merge:

In [1642]: result = df1.merge(df2, on='A')['B_y'].sum()

In [1643]: result
Out[1643]: 13