Accessing every 1st element of Pandas DataFrame column containing lists

As always, remember that storing non-scalar objects in frames is generally disfavoured, and should really only be used as a temporary intermediate step.

That said, you can use the .str accessor even though it's not a column of strings:

>>> df = pd.DataFrame({"A": [[1,2],[3,4],[8,9],[2,6]]})
>>> df["new_col"] = df["A"].str[0]
>>> df
        A  new_col
0  [1, 2]        1
1  [3, 4]        3
2  [8, 9]        8
3  [2, 6]        2
>>> df["new_col"]
0    1
1    3
2    8
3    2
Name: new_col, dtype: int64

You can use map and a lambda function

df.loc[:, 'new_col'] = df.A.map(lambda x: x[0])

---

Use apply with x[0]:

df['new_col'] = df.A.apply(lambda x: x[0])
print df
        A  new_col
0  [1, 2]        1
1  [3, 4]        3
2  [8, 9]        8
3  [2, 6]        2