python-pandas的基本用法12

pandas的基本用法12-整数索引

# -*- coding: utf-8 -*-

import numpy as np
import sys
from pandas import Series, DataFrame

print '整数索引'
ser = Series(np.arange(3.))
print ser
try:
print ser[-1] # 这里会有歧义
except:
print sys.exc_info()[0]
ser2 = Series(np.arange(3.), index = ['a', 'b', 'c'])
print ser2[-1]
ser3 = Series(range(3), index = [-5, 1, 3])
print ser3.iloc[2]  # 避免直接用[2]产生的歧义
print

print '对DataFrame使用整数索引'
frame = DataFrame(np.arange(6).reshape((3, 2)), index = [2, 0, 1])
print frame
print frame.iloc[0]
print frame.iloc[:, 1]