随笔分类 -  pandas学习

摘要:DataFrame的基本操作 1,选择 (1),Select column In [11]: df['a']Out[11]:0 -1.3552631 0.0108882 1.5995833 0.0045654 0.460270Name: a, dtype: float64(2),Select row by label In [15]: df... 阅读全文
posted @ 2014-06-28 09:20 sxcww 阅读(390) 评论(0) 推荐(0)
摘要:import pandas as pdSeries 类似于一维数组的对象t=pd.Series([1,2,3,4,5])print(t)'''0 11 22 33 44 5dtype: int64'''t=pd.Series([1,2,3,4,5],index=['a'... 阅读全文
posted @ 2014-04-23 21:35 sxcww 阅读(579) 评论(0) 推荐(0)
摘要:1.dot a,两个一维数组,计算对应下面元素的乘积和,也就是所谓的内积。 x=np.array([1,2,3,4])y=np.array([1,2,3,4])z=np.dot(x,y)print(z) //30 b,对于二维数组,矩阵乘积 x=np.array([[1,3],[2,4]])y=np.array([[5,7],[6,8]])z=np.dot(x,y)... 阅读全文
posted @ 2014-04-17 16:17 sxcww 阅读(1774) 评论(0) 推荐(0)
摘要:ogrid用切片作为下标,返回的是一组可用来广播计算的数组。其切片下标有如下形式: 1,[ 开始值:结束值:步长 ] x,y=np.ogrid[1:4:1,1:5:2]print(x)print(y)结果为:[[1] [2] [3]][[1 3]] 2,[ 开始值:结束值:长度j ] x,y=np.ogrid[1:4:3j,1:5:2j]pri... 阅读全文
posted @ 2014-04-17 15:41 sxcww 阅读(5308) 评论(0) 推荐(0)
摘要:import jsonimport pandas as pdimport numpy as npimport matplotlib.pyplot as pltif __name__=="__main__": path="usagov_bitly_data2012-03-16-1331923249.txt" fp=open(path) records=[json.loads(line) for line in fp.readlines()] print(len(records)) frame=pd.DataFrame(records) print(fram 阅读全文
posted @ 2014-04-09 22:12 sxcww 阅读(532) 评论(0) 推荐(0)
摘要:import jsonimport pandas as pdimport numpy as npimport matplotlib.pyplot as pltif __name__=="__main__": path="usagov_bitly_data2012-03-16-1331923249.txt" fp=open(path) records=[json.loads(line) for line in fp.readlines()] print(len(records)) frame=pd.DataFrame(records) print(fram 阅读全文
posted @ 2014-04-09 21:52 sxcww 阅读(247) 评论(1) 推荐(0)