R help - Dec 2008 - loop with dates

Hello,

I am trying to do a loop with dates, but when I try to use the index is not
a date.

   Fcorte <-  as.Date('2008/11/30',format = "%Y/%m/%d")
   fini <- Fcorte + 1
   ffin <- seq(fini,by='months',length=2)[2] - 1

   for (i in seq(fini,to = ffin, by='days'))
    print (weekdays(i))  # i doesn't a date

How can I do a loop with dates and get the index of each date? are there a
method to convert the index i to date?


Thanks in advance.

	[[alternative HTML version deleted]]

Try this:

weekdays(seq(fini,to = ffin, by='days'))

or in a loop:

sapply(as.character(seq(fini,to = ffin, by='days')),
      function(d)weekdays(as.Date(d)))

On Fri, Dec 12, 2008 at 4:55 PM, Fernando Bizuet <fbizuet@gmail.com>
wrote:
> Hello,
>
> I am trying to do a loop with dates, but when I try to use the index is not
> a date.
>
>   Fcorte <-  as.Date('2008/11/30',format = "%Y/%m/%d")
>   fini <- Fcorte + 1
>   ffin <- seq(fini,by='months',length=2)[2] - 1
>
>   for (i in seq(fini,to = ffin, by='days'))
>    print (weekdays(i))  # i doesn't a date
>
> How can I do a loop with dates and get the index of each date? are there a
> method to convert the index i to date?
>
>
> Thanks in advance.
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

Try iterating over the index rather than the value of
each component:

s <- seq(fini,to = ffin, by='days')
for (i in seq_along(s)) print(s[[i]])


On Fri, Dec 12, 2008 at 1:55 PM, Fernando Bizuet <fbizuet at gmail.com>
wrote:
> Hello,
>
> I am trying to do a loop with dates, but when I try to use the index is not
> a date.
>
>   Fcorte <-  as.Date('2008/11/30',format = "%Y/%m/%d")
>   fini <- Fcorte + 1
>   ffin <- seq(fini,by='months',length=2)[2] - 1
>
>   for (i in seq(fini,to = ffin, by='days'))
>    print (weekdays(i))  # i doesn't a date
>
> How can I do a loop with dates and get the index of each date? are there a
> method to convert the index i to date?
>
>
> Thanks in advance.
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Fernando Bizuet
> Sent: Friday, December 12, 2008 12:55 PM
> To: r-help at r-project.org
> Subject: [R] loop with dates
> 
> Hello,
> 
> I am trying to do a loop with dates, but when I try to use 
> the index is not
> a date.
See ?"for". That help page mentions the following which can clarify
what
to expect 

"... The variable 'var' has the same type as 'seq'
..."

Small illustration,

fac  <- gl(5,1,labels=letters[1:5])
fac
[1] a b c d e
Levels: a b c d e

typeof(fac)
[1] "integer"

for(i in fac) print(i)
[1] 1
[1] 2
[1] 3
[1] 4
[1] 5

> 
>    Fcorte <-  as.Date('2008/11/30',format =
"%Y/%m/%d")
>    fini <- Fcorte + 1
>    ffin <- seq(fini,by='months',length=2)[2] - 1
> 
>    for (i in seq(fini,to = ffin, by='days'))
>     print (weekdays(i))  # i doesn't a date
typeof(ffin)
[1] "double"

As your index is no longer of class 'Date', you will get
Error in UseMethod("weekdays") : no applicable method for
"weekdays
> 
> How can I do a loop with dates and get the index of each 
> date? are there a
> method to convert the index i to date?
Here's one way 
dd <- seq(fini,to = ffin, by='days')
for (i in seq_along(dd)) print(dd[i])
> 
> 
> Thanks in advance.
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>