[R] format for as.Date and inserting missing rows in a data frame

[PIKAL Petr]

Hi

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Stefano Sofia
> Sent: Tuesday, March 04, 2014 11:58 AM
> To: r-help at r-project.org
> Subject: [R] format for as.Date and inserting missing rows in a data
> frame
>
> Dear R users,
> I have a very long data frame (50 years, more than 1.5 million rows) of
> daily rainfall data from about 80 raingouges.
> The data frame that I have been given looks like
>
> Raingouge_number Station_number Year Month Day Rainfall
> 2004 2230 1951 1 1 2.60
> 2004 2230 1951 1 2 0.40
> 2004 2230 1951 1 3 0.00
> 2004 2230 1951 1 4 0.00
> 2004 2230 1951 1 5 0.20
> 2004 2230 1951 1 6 0.00
> 2004 2230 1951 1 7 0.00
> 2004 2230 1951 1 8 0.00
> 2004 2230 1951 1 9 0.00
> 2004 2230 1951 1 10 0.00
> ...
>
> There could be some missing days. I have two questions.
> 1st question:
> In order to handle eventual missing days I think that I have to
> transform three separate numbers (Year, Month and Day) to Date.
> Is there a format in as.Date suitable for this transformation or before
> all I have to set all the months and days to two digits, remove spaces
> and then apply as.Date with format "%Y%m%d"?

This shall do it if you put dataframe name instead of ...
as.Date(paste(...$Year, ...$Month, ...$Day, sep="."), format="%Y.%m.%d")

>
> 2nd question
> In case of missing day, the corresponding row will be missing and then
> I have to insert this new row and put -999.9 as Rainfall. Is there an
> easy way to do that?

Why? What is wrong with NA? What do you want to do with -999.9?
Anyway, you can get sequence of dates
?seq.Date

and merge it with your data.
?merge

I do not help you to put -999.9 instead of NA as I consider it extremely silly.

Regards
Petr

>
>
> Thank you for your help
> Stefano
>
>
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