我定义了一个多索引数据框,例如as:
import pandas as pd
import numpy as np
dates = pd.date_range('20130101',periods=3,freq='5s')
dates = dates.append(dates)
locations = list('AAABBB')
gascode = ['no2','o3','so2']*2
tup = pd.MultiIndex.from_tuples( zip(locations,gascode,dates), names=['Location','gas','Date'] )
data = pd.DataFrame(data=range(6),index=tup,columns=['val1'])
>>> data
Location gas Date val1
A no2 2013-01-01 00:00:00 0
o3 2013-01-01 00:00:05 1
so2 2013-01-01 00:00:10 2
B no2 2013-01-01 00:00:00 3
o3 2013-01-01 00:00:05 4
so2 2013-01-01 00:00:10 5
仅从位置'A'保存数据:
data = data.xs(key='A',level='Location')
现在,我想根据'gas'索引创建新列以产生:
Date no2 o3 so2
2013-01-01 00:00:00 0 nan nan
2013-01-01 00:00:05 nan 1 nan
2013-01-01 00:00:10 nan nan 2
我试图绕过'date'索引将'gas'放到列中,尽管这失败了。
data = data.pivot(index=data.index.get_level_values(level='date'),
columns=situ.index.get_level_values(level='gas'))
我无法实现这一目标;任何人都可以推荐替代品?
答案 0 :(得分:4)
您可以unstack
结果:
In [11]: data.xs(key='A', level='Location').unstack(0)
Out[11]:
val1
gas no2 o3 so2
Date
2013-01-01 00:00:00 0 NaN NaN
2013-01-01 00:00:05 NaN 1 NaN
2013-01-01 00:00:10 NaN NaN 2
[3 rows x 3 columns]