How to check whether the content of Column A is contained in Column B using Python DataFrame?

Question

I have two columns in a pandas DataFrame: authors and name. I want to create a third column: a cell\'s value is True if the correspond

Answer 1

IIUC then you can apply a lambda row-wise to check if the Name string is present in Authors:

df['Check'] = df.apply(lambda row: row['Name'] in row['Authors'], axis=1)

should work

You can't use str.contains(), str.extract(), str.find(), or where()here because you're trying to compare row-wise and those methods expect a fixed list or pattern for the searching criteria.

Answer 2

Here is a vectorized solution, which uses Series.str.split() and DataFrame.isin() methods:

df['Check'] = df.Authors.str.split(r'\s*,\s*', expand=True).isin(df.Name).any(1)

Demo:

In [126]: df
Out[126]:
                 Authors     Name
0  S.Rogers, T. Williams   H. Tov
1      M. White, J.Black  J.Black

In [127]: df.Authors.str.split(r'\s*,\s*', expand=True)
Out[127]:
          0            1
0  S.Rogers  T. Williams
1  M. White      J.Black

In [128]: df.Authors.str.split(r'\s*,\s*', expand=True).isin(df.Name)
Out[128]:
       0      1
0  False  False
1  False   True

In [130]: df['Check'] = df.Authors.str.split(r'\s*,\s*', expand=True).isin(df.Name).any(1)

In [131]: df
Out[131]:
                 Authors     Name  Check
0  S.Rogers, T. Williams   H. Tov  False
1      M. White, J.Black  J.Black   True