看來你需要get_loc
用於在index
value
然後iloc
位置選擇:
pos = df.index.get_loc(d)
print (df.iloc[[pos - 1]])
樣品:
start = pd.to_datetime('2016-11-30')
rng = pd.date_range(start, periods=10, freq='M')
df = pd.DataFrame({'a': range(10)}, index=rng)
print (df)
a
2016-11-30 0
2016-12-31 1
2017-01-31 2
2017-02-28 3
2017-03-31 4
2017-04-30 5
2017-05-31 6
2017-06-30 7
2017-07-31 8
2017-08-31 9
d = '2017-01-31'
pos = df.index.get_loc(d)
print (df.iloc[[pos - 1]])
a
2016-12-31 1
如果date
不index
添加method='nearest'
:
d = '2017-01-20'
pos = df.index.get_loc(d, method='nearest')
print (df.iloc[[pos - 1]])
a
2016-12-31 1
但是,如果你有需要更廣泛的解決方案中使用了一些條件,如:
d = '2017-11-30'
pos = df.index.get_loc(d, method='nearest')
if pos == 0:
print ('Value less or same as minimal date in DataTimeIndex')
else:
print ('Value nearest less or same as date', df.index[pos])
print ('Previous value', df.iloc[[pos - 1]])
曾爲真棒謝謝! – datascana