python - 在 pandas python 中删除 NaN

Question

无法弄清楚为什么 .dropnan() 没有删除具有 NaN 值的单元格？

请帮忙，我已经浏览了 pandas 文档，不知道我做错了什么？？？

import pandas as pd
import quandl

import pandas as pd

df = quandl.get("GOOG/NYSE_SPY")
df2 = quandl.get("YAHOO/AAPL")

date = pd.date_range('2010-01-01', periods = 365)

df3 = pd.DataFrame(index = date)

df3 = df3.join(df['Open'], how = 'inner')

df3.rename(columns = {'Open': 'SPY'}, inplace = True)

df3 = df3.join(df2['Open'], how = 'inner')

df3.rename(columns = {'Open': 'AAPL'}, inplace = True)

df3['Spread'] = df3['SPY'] / df3['AAPL']

df3 = df3 / df3.ix[0]

df3.dropna(how = 'any')

df3.plot()

print(df3)

Answer 1

将df3.dropna(how = 'any')更改为df3 = df3.dropna(how = 'any')