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st: RE: Categorising dates
From
Nick Cox <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
st: RE: Categorising dates
Date
Tue, 24 Aug 2010 15:33:40 +0100
To get any distance in working with dates, you need to study the menagerie of associated functions. Start at -help dates-.
The second question, which looks simpler, is ambiguous. Do you mean just month, so that
Month of 24 August 2010 := August
-- or do you really mean year and month, so that
Month of 24 August 2010 := August 2010
?
For the first, use -month()-. For the second use, -mofd()-. Examples:
. di month(mdy(8,24,2010))
8
. di mofd(mdy(8,24,2010))
607
. di %tmm_Cy mofd(mdy(8,24,2010))
Aug 2010
The second question looks less simple but is clear. Stata has a -dow()- function yielding day of the week, coded 0 for Mondays through 6 for Saturdays. Therefore the previous Monday is given by
gen mondays = cond(dow(day) == 0, day - 6, day - dow(day) + 1)
i.e. 6 days before any Sunday, etc.
This variable codes days by the previous Monday, and so classifies weeks accordingly.
There may well be a simpler way to do it.
Nick
[email protected]
sara khan
I have a list of daily dates inthe format, for example, 23 Sep 09, and
need to create two variables. One is to categorise the days into
weekly data (so week commencing on a Monday). The second is to create
a variable cataegorsing the daily data into monthly data.
I would be grateful for advice on how to do this.
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