import pandas as pdimport numpy as npfrom pandas import DataFrame,Series# 使用 Dataframe的列作為索引frame = DataFrame({'a':range(7),'b':range(7,0,-1), 'c':['one','one','one','two','two','two','two'], 'd':[0,1,2,0,1,2,3]})frameframe2 = frame.set_index(['c','d']) # set_index 函數(shù)可以將一個(gè)或者多個(gè)列轉(zhuǎn)成行的索引并且創(chuàng)建一個(gè)新的dataframeframe2frame.set_index(['c','d'],drop=False) # 會(huì)自動(dòng)把 c d 兩列去掉,可以添加drop參數(shù)來決定他們的去留frame2.reset_index() # 和set_index相反,層次化的索引會(huì)被加入到列里面# 面板數(shù)據(jù)import pandas.io.data as webpdata = pd.Panel(dict((stk,web.get_data_yahoo(stk,'1/1/2009','6/1/2012')) for stk in ['AAPL','GOOG','MSFT','DELL'])) # 由一個(gè)DataFrame對(duì)象組成的字典或者三維ndaray創(chuàng)建panel對(duì)象pdatapdata = pdata.swapaxes('items','minor')pdata['Adj Close']pdata.ix[:,'6/1/2012',:]pdata.ix['Adj Close','5/22/2012':,:]stacked = pdata.ix[:,'5/30/2012'].to_frame()stacked.to_panel() # to_frame()的逆運(yùn)算
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