pandas之索引、选取和过滤

《利用python进行数据分析》相应章节

obj=Series(np.arange(4.),index=['a','b','c','d'])from pandas import *import pandas as pdobj=Series(np.arange(4.),index=['a','b','c','d'])objobj['b']obj[1]obj[2:4]obj[['b','a','d']]objobj[[1,3]]obj[obj<2]obj['b':'c']obj['b':'c']=5objdata=DataFrame(np.arange(16).reshape((4,4)),index=['Ohio','Colorado','Utah','New York'],columns=['one','two','three','four'])datadata['two']data['three','one']data[['three','one']]datadata[:2]data[data['three']>5]data<5data[data<5]=0datadata.ix['Colarado',['two','three']]data.ix['Colorado',['two','three']]data.ix['Colorado',[3,0,1]]datadata.ix[2]data.ix[:'Utah','two']datadata.ix[data.three>5,:3]