📅  最后修改于: 2022-03-11 14:46:21.230000             🧑  作者: Mango
In [3]: df = pd.DataFrame({"A": ["a", "b", "c", "a"]})
In [4]: df["B"] = df["A"].astype('category')
In [5]: df
Out[5]:
A B
0 a a
1 b b
2 c c
3 a a