R help - Apr 2012 - difficulty in Formatting time series data

Dear R-Gurus

I have a data frame (from CSV file) which has its first column called Date.
The Date is in the format mm/dd/yyyy. I was trying to get the weekday for
these dates and I tried using wday() and day.of.week() functions and both
of them gave me precisely the wrong answers. I think the issue lies in the
proper formatting of dates. The class of this column is a factor class and
hence I tried converting into POSIXlt, xts, zoo objects and yet I could not
get the weekday correctly. Anyone has any suggestions please?

Many thanks
Raghu

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Yes.... dput() for a reproducible example with some minimal
reproducible code (and the packages "day.of.week" and wday() come
from...)

x <- xts(10, Sys.Date())
wday(x)

seems fine for me.

"precisely the wrong answers"  -- interesting turn of phrase.

Michael

On Sun, Apr 22, 2012 at 12:53 PM, Raghuraman Ramachandran
<optionsraghu at gmail.com> wrote:
> Dear R-Gurus
>
> I have a data frame (from CSV file) which has its first column called Date.
> The Date is in the format mm/dd/yyyy. I was trying to get the weekday for
> these dates and I tried using wday() and day.of.week() functions and both
> of them gave me precisely the wrong answers. I think the issue lies in the
> proper formatting of dates. The class of this column is a factor class and
> hence I tried converting into POSIXlt, xts, zoo objects and yet I could not
> get the weekday correctly. Anyone has any suggestions please?
>
> Many thanks
> Raghu
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Raghu,

On 22 April 2012 09:53, Raghuraman Ramachandran
<optionsraghu@gmail.com>wrote:
> I have a data frame (from CSV file) which has its first column called Date.
> The Date is in the format mm/dd/yyyy. I was trying to get the weekday for
> these dates and I tried using wday() and day.of.week() functions and both
> of them gave me precisely the wrong answers. I think the issue lies in the
> proper formatting of dates. The class of this column is a factor class and
> hence I tried converting into POSIXlt, xts, zoo objects and yet I could not
> get the weekday correctly. Anyone has any suggestions please?
>
Try this:
# assume dataIn is where the CSV files data is...
dataIn$Date <- as.POSIXct(dataIn$Date, format='%m/%d/%y')
dataIn <- cbind(dataIn, day.of.week = format(dataIn$Date,
format='%A')

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