Pandas：如何确定列值是否在另一列的列表中

Question

Goal: I have this dataframe where I want to see if a "Country" belongs to "Another Country's Neighbors" list:

Country     AnotherCountry  AnotherCountryNeighbors
A           X                [B, C]
A           Y                [A, B]

Expected output: If the country is a neighbor, I'd like to add a column "Country Neighbor", which is a boolean value:

Country     AnotherCountry  AnotherCountryNeighbors   CountryNeighbor
A           X                [B, C]                    False
A           Y                [A, B]                    True

Attempt: I tried using the dataframe.isin() function:

df.Country.isin(df.AnotherCountryNeighbors)

Error:

TypeError: unhashable type: 'list'

Answer 1

Using in with apply

df.apply(lambda x :  x['Country'] in x['AnotherCountryNeighbors'],1)
Out[1425]: 
0    False
1     True
dtype: bool

Your AnotherCountryNeighbors is list , isin can not work with list values : iterable, Series, DataFrame or dictionary

Answer 2

这是我发现列表理解+ zip可读和高效与pandas一个场合：

df['CountryNeighbor'] = [i in j for i, j in zip(df.Country, df.AnotherCountryNeighbors)]