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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第
7
章
处理日期和时间
0 2002-02-28 00:00:00+00:00
1 2002-03-31 00:00:00+00:00
2 2002-04-30 00:00:00+00:00
dtype: datetime64[ns, Africa/Abidjan]
讨论
pandas
支持两种表示时区的字符串，但是我建议使用
pytz
库的字符串。导入
all_
timezones
库就能看到所有代表时区的字符串 ：
#
加载库
from pytz import all_timezones
#
查看两个时区
all_timezones[0:2]
['Africa/Abidjan', 'Africa/Accra']
7.3
选择日期和时间
问题描述
从一组日期向量中选择一个或多个日期值。
解决方案
使用两个布尔条件句分别设置开始日期和结束日期 ：
#
加载库
import pandas as pd
#
创建数据帧
dataframe = pd.DataFrame()
#
创建
datetime
dataframe['date'] = pd.date_range('1/1/2001', periods=100000, freq='H')
#
筛选出两个日期之间的观察值
dataframe[(dataframe['date'] > '2002-1-1 01:00:00') &
(dataframe['date'] <= '2002-1-1 04:00:00')]
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