pandas 熊猫生成开始月份的日期范围
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/21420165/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Pandas generate date range of Beginning Month
提问by dartdog
What is going on here? I need to generate a dataframe with beginning of month dates,,(1-1-2014 To 12-1-2014) fwiw I use the fcast_year variable elsewhere where I need the end of month, hence doing date math
这里发生了什么？我需要生成一个带有月初日期的数据框，(1-1-2014 到 12-1-2014) fwiw 我在其他需要月底的地方使用 fcast_year 变量，因此做日期数学
from pandas.tseries.offsets import *
fcast_yr=pd.to_datetime('2014-12-31')
x=(fcast_yr + pd.DateOffset(days= -30)) # to set x to 2014-12-01
d=pd.date_range((x +pd.DateOffset(months=-10)), periods=12, freq='MS') #"MS" means start of month!!
print d.values
Gives these end of month values....yech!!
给出这些月末值....耶！
['2014-01-31T18:00:00.000000000-0600' '2014-02-28T18:00:00.000000000-0600'
'2014-03-31T19:00:00.000000000-0500' '2014-04-30T19:00:00.000000000-0500'
'2014-05-31T19:00:00.000000000-0500' '2014-06-30T19:00:00.000000000-0500'
'2014-07-31T19:00:00.000000000-0500' '2014-08-31T19:00:00.000000000-0500'
'2014-09-30T19:00:00.000000000-0500' '2014-10-31T19:00:00.000000000-0500'
'2014-11-30T18:00:00.000000000-0600' '2014-12-31T18:00:00.000000000-0600']
Using 13.0 pf Pandas
使用 13.0 pf Pandas
回答by Jeff
You don't need to coerce the timestamp to the begin month; the frequency will do it (but your answer is correct).
您不需要将时间戳强制为开始月份；频率会做到这一点（但你的答案是正确的）。
The 'values' are just the way numpy represents dates (they are UTC).
“值”只是 numpy 表示日期的方式（它们是 UTC）。
In [8]: pd.date_range((Timestamp('20141231') +pd.DateOffset(months=-11)), periods=12, freq='MS')
Out[8]:
<class 'pandas.tseries.index.DatetimeIndex'>
[2014-02-01, ..., 2015-01-01]
Length: 12, Freq: MS, Timezone: None
