与列表类型列的逐行比较

Question

let's assume I have the following code

import pandas as pd

df = pd.DataFrame({'List type':[[1, 2, 3], [4, 5, 6], [7, 8, 9]], 'Integer type':[5, 4, 1]})

and resulting Pandas dataframe:

| List-type | Integer-type |
| --------  | -------------|
| [1, 2, 3] |      5       |
| [4, 5, 6] |      4       |
| [7, 8, 9] |      1       |

Is there a way to compare the integer-type values against the respective list in the same row without using a for loop, or the itertools package? Basically what I want is a mask to filter for the rows where the integer is contained in the list. I could not get methods like isin (requires the list already as argument, which requires row-wise indexing) or general comparisons to work (compares the list against the integer) so far. Help is appreciated!

Answer 1

One way using pandas.DataFrame.apply :

df["mask"] = df.apply(lambda x: x["Int-type"] in x["List-type"], axis=1)
print(df)

Output:

   List-type  Int-type   mask
0  [1, 2, 3]         5  False
1  [4, 5, 6]         4   True
2  [7, 8, 9]         1  False

Answer 2

Try with explode

s = df.explode('List type')
df['new'] = s["Integer type"].eq(s["List type"]).any(level=0)
df
Out[35]: 
   List type  Integer type    new
0  [1, 2, 3]             5  False
1  [4, 5, 6]             4   True
2  [7, 8, 9]             1  False