python - 三次样条插值仅产生 nans 或引发错误

Question

我正在尝试从每季度到每月对数据框进行下采样。

i = ['2000-01-01','2000-04-01','2000-07-01','2000-10-01','2001-01-01','2001-04-01','2001-07-01','2001-10-01']
d = [0,54957.84767,0,0,0,56285.54879,0,0]

df = pd.DataFrame(index=i, data=d)
df.index = pd.to_datetime(df.index,infer_datetime_format=True)
df.index = df.index.to_period('Q')

df.resample('M').interpolate(method='cubic')

这会引发 TypeError：

TypeError: ufunc 'isnan' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

如果我跳过这一行：

    df.index = df.index.to_period('Q')

然后它只会产生nans

Answer 1

这有效：

import pandas as pd
import matplotlib.pyplot as plt

i = pd.to_datetime(['2000-01-01','2000-04-01','2000-07-01','2000-10-01','2001-01-01','2001-04-01','2001-07-01','2001-10-01'])
d = [0,54957.84767,0,0,0,56285.54879,0,0]

df = pd.DataFrame({'Values': d}, index=i)
df_resampled = df.resample('M').first().interpolate(method='cubic')

# Display the fit
df['Values'].plot(linestyle='none', marker='D', color='red')
df_resampled['Values'].plot(label='fit')
plt.xlabel('Date')
plt.ylabel('Values, a.u.')
plt.legend()