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无法在Jupyter笔记本单元中再次加入熊猫数据帧

jupyter-notebook pandas python

Unnikrishnan · 技术社区 · 7 年前

我要加两个新的 SMA 列到我的数据帧,使用 pandas.DataFrame.join 功能。

第一次运行正常,但如果再次运行该单元,将收到以下错误:

ValueError: columns overlap but no suffix specified: Index(['SMA_LONG'], dtype='object')

以下是我的代码。

#cell 1
import numpy as np
import pandas as pd

#cell 2
df = pd.DataFrame({
   'close': np.random.uniform(0.1,0.9, 100),
})

#cell 3
SMA_long = 12
SMA_short = 7
sma_long = df['close'].rolling(window=SMA_long, min_periods=SMA_long - 1).mean()
df = df.join(sma_long.to_frame('SMA_LONG'))

sma_short = df['close'].rolling(window=SMA_short, min_periods=SMA_short - 1).mean()
df = df.join(sma_short.to_frame('SMA_SHORT'))

df.tail()

我怎么能解决这个问题?

谢谢。

1 回复 | 直到 7 年前

jezrael 7 年前

你的错误意味着已经 SMA_LONG 之前 df = df.join(sma_long.to_frame('SMA_LONG')) .

对于我来说,您的示例数据解决方案工作得很好,但我认为您可以通过分配给新列来简化它:

SMA_long = 12
SMA_short = 7
df['SMA_LONG'] = df['close'].rolling(window=SMA_long, min_periods=SMA_long - 1).mean()
df['SMA_SHORT'] = df['close'].rolling(window=SMA_short, min_periods=SMA_short - 1).mean()

print (df)
       close  SMA_LONG  SMA_SHORT
0   0.649439       NaN        NaN
1   0.332926       NaN        NaN
2   0.492527       NaN        NaN
3   0.500444       NaN        NaN
4   0.583334       NaN        NaN
..       ...       ...        ...
95  0.775169  0.532850   0.577613
96  0.470479  0.524123   0.594733
97  0.237417  0.517054   0.512506
98  0.753701  0.536595   0.554372
99  0.133795  0.526603   0.475595

[100 rows x 3 columns]

或:

sma_long = df['close'].rolling(window=SMA_long, min_periods=SMA_long - 1).mean()
sma_short = df['close'].rolling(window=SMA_short, min_periods=SMA_short - 1).mean()

df = df.assign(SMA_LONG=sma_long, SMA_SHORT=sma_short)

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