python - Check if value from one dataframe exists in another dataframe

Question

I have 2 dataframes.

Df1 = pd.DataFrame({'name': ['Marc', 'Jake', 'Sam', 'Brad']
Df2 = pd.DataFrame({'IDs': ['Jake', 'John', 'Marc', 'Tony', 'Bob']

I want to loop over every row in Df1['name'] and check if each name is somewhere in Df2['IDs'].

The result should return 1 if the name is in there, 0 if it is not like so:

Marc  1 
Jake  1
Sam   0 
Brad  0

Thank you.

Answer 1

Use isin

Df1.name.isin(Df2.IDs).astype(int)

0    1
1    1
2    0
3    0
Name: name, dtype: int32

---

Show result in data frame

Df1.assign(InDf2=Df1.name.isin(Df2.IDs).astype(int))

   name  InDf2
0  Marc      1
1  Jake      1
2   Sam      0
3  Brad      0

---

In a Series object

pd.Series(Df1.name.isin(Df2.IDs).values.astype(int), Df1.name.values)

Marc    1
Jake    1
Sam     0
Brad    0
dtype: int32