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Start and End day of a month

6 messages · Rantony, R. Michael Weylandt, Joshua Ulrich +2 more

Rantony
# 
Hi,

Can anyone please help to get "StartDay" and "End-day of a particular month"
with time ?

For eg:- Input wil be "2012-09-27"

i need to get output as given below

StartDt <- "2012-09-01 00:00:01"
EndDt <- "2012-09-30 23:59:59"

- Thanks in advance



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R. Michael Weylandt
#
On Thu, Sep 27, 2012 at 1:21 PM, Rantony <antony.akkara at ge.com> wrote:
Look at xts::lastof().

Cheers,
Michael
arun
# 
HI, 
For a vector of dates:
Using Michael's suggestion: 
library(xts) 
library(zoo) 
Dt<-c("2012-09-27","2012-09-28","2012-07-24","2012-06-05","2012-12-03") 
newDt<-strsplit(format(as.yearmon(Dt),"%Y-%m"),split="-") 
StartDt<-do.call(rbind,lapply(lapply(lapply(newDt,`[`,1:2),function(x)
 as.numeric(c(x[1],x[2]))),function(x) 
format(firstof(x[1],x[2],sec=1),format="%Y-%m-%d %r"))) 
EndDt<-do.call(rbind,lapply(lapply(lapply(newDt,`[`,1:2),function(x)
 as.numeric(c(x[1],x[2]))),function(x) 
format(lastof(x[1],x[2]),format="%Y-%m-%d %r"))) 
dat1<-data.frame(inputDate=Dt,StartDt=StartDt,EndDt=EndDt) 
dat1 
# ? inputDate ? ? ? ? ? ? ? ?StartDt ? ? ? ? ? ? ? ? ?EndDt 
#1 2012-09-27 2012-09-01 12:00:01 AM 2012-09-30 11:59:59 PM 
#2 2012-09-28 2012-09-01 12:00:01 AM 2012-09-30 11:59:59 PM 
#3 2012-07-24 2012-07-01 12:00:01 AM 2012-07-31 11:59:59 PM 
#4 2012-06-05 2012-06-01 12:00:01 AM 2012-06-30 11:59:59 PM 
#5 2012-12-03 2012-12-01 12:00:01 AM 2012-12-31 11:59:59 PM 

A.K. 



----- Original Message -----
From: R. Michael Weylandt <michael.weylandt at gmail.com>
To: Rantony <antony.akkara at ge.com>
Cc: r-help at r-project.org
Sent: Thursday, September 27, 2012 11:33 AM
Subject: Re: [R] Start and End day of a month
On Thu, Sep 27, 2012 at 1:21 PM, Rantony <antony.akkara at ge.com> wrote:
Look at xts::lastof().

Cheers,
Michael

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Joshua Ulrich
#
On Thu, Sep 27, 2012 at 3:05 PM, arun <smartpink111 at yahoo.com> wrote:
That code is very difficult to follow.  This is much clearer:

dat1 <- data.frame(inputDate=Dt,
  startDate=do.call(c,lapply(Dt, firstof, 0, 0, 1)),
  endDate=do.call(c,lapply(Dt, lastof, 23, 59, 59)))

--
Joshua Ulrich  |  about.me/joshuaulrich
FOSS Trading  |  www.fosstrading.com
arun
# 
HI Joshua,

Thanks for providing much easier solution.

But, I am getting the output from dat1 as:
#? inputDate?????????? startDate???????????? endDate
#1 2012-09-27 2012-09-27 00:00:01 2012-09-27 23:59:59
#2 2012-09-28 2012-09-28 00:00:01 2012-09-28 23:59:59
#3 2012-07-24 2012-07-24 00:00:01 2012-07-24 23:59:59
#4 2012-06-05 2012-06-05 00:00:01 2012-06-05 23:59:59
#5 2012-12-03 2012-12-03 00:00:01 2012-12-03 23:59:59

OP's request: 

"Can anyone please help to get "StartDay" and "End-day of a particular date" with time ? 
For eg:- Input wil be "2012-09-27" 
i need to get output as given below 

StartDt <- "2012-09-01 12:00:01 AM" 
EndDt <- "2012-09-30 11:59:59 PM" "

May be there is something you forgot to add in the reply.

A.K.





----- Original Message -----
From: Joshua Ulrich <josh.m.ulrich at gmail.com>
To: arun <smartpink111 at yahoo.com>
Cc: Rantony <antony.akkara at ge.com>; R help <r-help at r-project.org>
Sent: Thursday, September 27, 2012 11:26 PM
Subject: Re: [R] Start and End day of a month
On Thu, Sep 27, 2012 at 3:05 PM, arun <smartpink111 at yahoo.com> wrote:
That code is very difficult to follow.? This is much clearer:

dat1 <- data.frame(inputDate=Dt,
? startDate=do.call(c,lapply(Dt, firstof, 0, 0, 1)),
? endDate=do.call(c,lapply(Dt, lastof, 23, 59, 59)))

--
Joshua Ulrich? |? about.me/joshuaulrich
FOSS Trading? |? www.fosstrading.com
Gabor Grothendieck
#
On Thu, Sep 27, 2012 at 8:21 AM, Rantony <antony.akkara at ge.com> wrote:
This converts the input to a "yearmon" class object which represents
the date as just a year and month.  We then convert it back to "Date"
class using the frac argument to indicate whether the first or last of
the month is to be used.  Finally we paste the time to it which also
converts it to character.

library(zoo)

d <- "2012-09-27"
ym <- as.yearmon(d)

StartDt <- paste(as.Date(ym, frac = 0), "00:00:01")
EndDt <- paste(as.Date(ym, frac = 1), "23:59:59")