以下是如何使用某些整数索引值进行插值的示例：

#!/usr/bin/env ipython
import numpy as np
import pandas as pd
import datetime
# --------------------------------------------------------------
# let us generate the sample data, similar to data in question:
dvec = [datetime.datetime(1818,1,1)+ii*datetime.timedelta(days=1) for ii in range(200*365)]
# --------------------------------------------------------------
yy = [vv.year for vv in dvec]
mm = [vv.month for vv in dvec]
dd = [vv.day for vv in dvec]
c1 = np.random.random(np.size(yy))
c2 = np.random.random(np.size(yy))
c3 = np.random.random(np.size(yy))
datain = np.vstack((yy,mm,dd,c1,c2,c3)).T
# --------------------------------------------------------------
# let us convert our data to pandas dataframe:
ddict = {ii:datain[:,ii] for ii in range(datain.shape[1])}
# we can also add just some index values for the interpolation:
# --------------------------------------------------------------
# let us interpolate to wished values using integer values:
kk = [kk for kk,val in enumerate(dvec,1) if val.year>=1900 and val.year<2000]
iout = np.linspace(kk[0],kk[-1],1000)
ddict['index'] = np.linspace(1,datain.shape[0],datain.shape[0])
# ------------------------------------------------------------
df = pd.DataFrame.from_dict(ddict);
dfi = df.set_index('index');
dfo = dfi.reindex(dfi.index|iout) # add new index values to the dataframe
dfo = dfo.interpolate(method='linear').loc[iout]