python-polars 使用字典按列值将数据帧拆分为多个 dfs

Question

我想使用字典通过唯一列值将单个 df 拆分为多个 df。下面的代码展示了如何使用 pandas 来完成此操作。我怎样才能在极地中执行以下操作？

import pandas as pd

#Favorite color of 10 people
df = pd.DataFrame({"Favorite_Color":["Blue","Yellow","Black","Red","Blue","Blue","Green","Red","Red","Blue"]})

#split df into many dfs by Favorite_Color using dict
dict_of_dfs={key: df.loc[value] for key, value in df.groupby(["Favorite_Color"]).groups.items()}
print(dict_of_dfs)

Answer 1

Polars 有一个用于此目的的 DataFrame 方法：

partition_by

。 使用

as_dict

关键字创建 DataFrame 字典。

df.partition_by("Favorite_Color", as_dict=True)

{('Blue',): shape: (4, 1)
 ┌────────────────┐
 │ Favorite_Color │
 │ ---            │
 │ str            │
 ╞════════════════╡
 │ Blue           │
 │ Blue           │
 │ Blue           │
 │ Blue           │
 └────────────────┘,
 ('Yellow',): shape: (1, 1)
 ┌────────────────┐
 │ Favorite_Color │
 │ ---            │
 │ str            │
 ╞════════════════╡
 │ Yellow         │
 └────────────────┘,
 ('Black',): shape: (1, 1)
 ┌────────────────┐
 │ Favorite_Color │
 │ ---            │
 │ str            │
 ╞════════════════╡
 │ Black          │
 └────────────────┘,
 ('Red',): shape: (3, 1)
 ┌────────────────┐
 │ Favorite_Color │
 │ ---            │
 │ str            │
 ╞════════════════╡
 │ Red            │
 │ Red            │
 │ Red            │
 └────────────────┘,
 ('Green',): shape: (1, 1)
 ┌────────────────┐
 │ Favorite_Color │
 │ ---            │
 │ str            │
 ╞════════════════╡
 │ Green          │
 └────────────────┘}