July 2019
Intermediate to advanced
365 pages
8h 13m
Chinese
Content preview from Python机器学习手册：从数据预处理到深度学习
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7.4
将日期数据切分成多个特征
｜
117
date
8762 2002-01-01 02:00:00
8763 2002-01-01 03:00:00
8764 2002-01-01 04:00:00
或者，将
date
（日期）这一列设为数据帧的索引列，然后用
loc
进行筛选 ：
#
设置索引
dataframe = dataframe.set_index(dataframe['date'])
#
选择两个日期之间的观察值
dataframe.loc['2002-1-1 01:00:00':'2002-1-1 04:00:00']
date
2002-01-01 01:00:00 2002-01-01 01:00:00
2002-01-01 02:00:00 2002-01-01 02:00:00
2002-01-01 03:00:00 2002-01-01 03:00:00
2002-01-01 04:00:00 2002-01-01 04:00:00
讨论
你需要根据场景来决定，是用布尔条件句还是用索引来筛选日期值。如果你想执行复杂
的时间序列操作，那么将
date
这一列设置为数据帧的索引是值得的 ；但是如果你只是想
做一些简单的数据整理工作，那么使用布尔条件句会更简单一些。
7.4
将日期数据切分成多个特征
问题描述
用一列日期和时间数据来创建年、月、日、时、分的特征。
解决方案
使用
pandas
函数
Series.dt
的时间属性 ：
#
加载库
import pandas as pd
#
创建数据帧
dataframe ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.