Equivalent of "in" keyword or subquery in pandas

Question

I have a Series object (let's call this MySeries) which contains a list of integers.

I also have a separate dataframe (say MyDataFrame), which includes a column/field called MyField.

I want to select all records from MyDataFrame where the value in MyField is in MySeries

The equivalent SQL would be:

Select * from MyDataFrame 
where MyField in 
    (select * from MySeries)

Could anyone suggest the best way to do this?

Thanks very much for any help.

Answer 1

you can use isin() function:

>>> df = pd.DataFrame({'A':[1,2,3,4,5], 'B':list('ABCDE')})
>>> f = pd.Series([1,2])
>>> df[df['A'].isin(f)]
   A  B
0  1  A
1  2  B

so, first you get fiter Series:

>>> df['A'].isin(f)
0     True
1     True
2    False
3    False
4    False

And then use it to filter your DataFrame