用嵌套字典创建一个多索引的“系列" [英] Creating a multiindexed `Series` with a nested dictionary

问题描述

在我看来，我要做的事情应该简单明了，就像将其传递给构造函数一样简单，但实际上并非如此.我有如下字典.

In my mind, what I'm trying to do ought to be straightforward, as straightforward as passing it into the constructor, but in reality it's not. I have a dictionary like below.

d = {"russell": {"score": numpy.random.rand(), "ping": numpy.random.randint(10, 100)},
    "cantor": {"score": numpy.random.rand(), "ping": numpy.random.randint(10, 100)},
    "godel": {"score": numpy.random.rand(), "ping": numpy.random.randint(10, 100)}}

我想做类似pandas.Series(d)的事情，并得到一个类似下面的Series实例.

I would like to do something like pandas.Series(d) and get a Series instance like below.

russell  score  0.87391482
         ping   23
cantor   score  0.77821932
         ping   16
godel    score  0.53372128
         ping   35

但是我实际上得到的是下面的东西.

But what I actually get is below.

cantor     {'ping': 44, 'score': 0.007408727109865398}
godel        {'ping': 41, 'score': 0.9338940910283948}
russell       {'ping': 74, 'score': 0.733817307366666}

有没有办法实现我想要达到的目标?

Is there a way to achieve something like what I'm trying to achieve?

推荐答案

我认为您需要 DataFrame 构造函数，带有

I think you need DataFrame constructor with unstack:

import pandas as pd
import numpy as np

d = {"russell": {"score": np.random.rand(), "ping": np.random.randint(10, 100)},
    "cantor": {"score": np.random.rand(), "ping": np.random.randint(10, 100)},
    "godel": {"score": np.random.rand(), "ping": np.random.randint(10, 100)}}

print (pd.DataFrame(d).unstack())  

cantor   ping     33.000000
         score     0.240253
godel    ping     64.000000
         score     0.435040
russell  ping     41.000000
         score     0.171810
dtype: float64

如果需要MultiIndex中的交换级别，请使用 stack :

Also if need swap levels in MultiIndex use stack:

print (pd.DataFrame(d).stack())    
ping   cantor     64.000000
       godel      40.000000
       russell    66.000000
score  cantor      0.265771
       godel       0.283725
       russell     0.085856
dtype: float64

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