pandas 在循环中设置数据帧的名称 [英] pandas set names of dataframes in loop

问题描述

我想创建多个数据框，这些数据框的名称与该列之一中的值相同.我希望这段代码像这样工作:

I want to create multiple dataframes of names that the same as values in one of the column. I would like this code to work like that:

import pandas as pd

data=pd.read_csv('athlete_events.csv')


Sports = data.Sport.unique()

for S in Sports:
    name=str(S)
    name=data.loc[data['Sport']==S]

推荐答案

您可以通过修改 globals()来做到这一点，但这并不是真正的建议.

You can do this by modifying globals() but that's not really adviseable.

for S in Sports:
    globals()[str(S)] = data.loc[data['Sport']==S]    

下面是一个独立的示例:

Below is a self-contained example:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'sport':['football', 'football', 'tennis'],
                           'value':[1, 2, 3]})

In [3]: df
Out[3]: 
      sport  value
0  football      1
1  football      2
2    tennis      3

In [4]: for name in df.sport.unique():
    ...:     globals()[name] = df.loc[df.sport == name]
    ...:     

In [4]: football
Out[4]: 
      sport  value
0  football      1
1  football      2

虽然这是对您问题的直接答案，但我建议使用sacul的答案，字典是为此目的(即存储键和值)而通过 globals()插入的变量名通常不是首先是个好主意.

While this is a direct answer to your question, I would recommend sacul's answer, dictionaries are meant for this (i.e. storing keys and values) and variable names inserted via globals() are usually not a good idea to begin with.

想象一下将来有其他人或您自己阅读代码-突然您正在使用 football ，就像以前从未明确定义过的 pd.DataFrame -你应该怎么知道怎么回事?

Imagine someone else or yourself in the future reading your code - all of a sudden you are using football like a pd.DataFrame which you have never explicitly defined before - how are you supposed to know what is going on?

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