Q:

How to operate on column value which is a list Python

I have a dataframe and one of the columns is a list. I want to go through each row and find a string in the list that starts with the letter 'A' and remove everything after and including the slash "/"
    Index      Entities
     0        ["Apple/1", "Applet/87", "Book/12", "Stable/0"]
     1        ["App/12", "orange/6", "Apples/7", "Stables/0"]

Given this dataframe as an input, I expect the new dataframe to look like this:
      Index      Entities
     0        ["Apple", "Applet", "Book/12", "Stable/0"]
     1        ["App", "orange/6", "Apples", "Stables/0"]

A:

IIUC
[[y.split('/', 1)[0] if y.startswith('A') else y for y in row] for row in df.Entities]

[['Apple', 'Applet', 'Book/12', 'Stable/0'],
 ['App', 'orange/6', 'Apples', 'Stables/0']]

df.assign(
    Entities=[
        [y.split('/', 1)[0] if y.startswith('A') else y
         for y in row] for row in df.Entities
    ]
)

   Index                            Entities
0      0  [Apple, Applet, Book/12, Stable/0]
1      1  [App, orange/6, Apples, Stables/0]

