python dataframe选择满足某条件的行，进行操作

import pandas as pd
data = {'state':['Ohio','Ohio','Merry','Nevaio','Nevada'],
    'year':[2000,2001,2002,2001,2002],
    'pop':[1.5,1.7,3.6,2.4,2.9]
}
frame = pd.DataFrame(data,columns=['year','state','pop','debt'],index=['one','two','three','four','five'])
frame

 

数据如上图所示，现找出state中'state'列中含有字符'io'的行，将其的debt列赋值为'aa',实现代码如下：

frame.ix[frame['state'].str.contains('io'),['debt']] = 'aa'
frame

现找出state中'state'列中等于‘Ohio’行，将其的debt列赋值为'aa',frame还是开头定义的，实现代码如下：

frame.ix[frame['state']=='Ohio',['debt']] = 'aa'
frame

多个选择条件时，用（‘&’、‘|’），如现找出state中'state'列中等于‘Ohio’行或者‘Merry’的行，用'|'，将其的debt列赋值为'aa',实现代码如下：

frame.ix[(frame['state']=='Ohio')|(frame['state']=='Merry'),['debt']] = 'aa'
frame