[R] means by year, month and day

[Jianling Fan]

Hello Tom,

try aggregate() or cast(). Both works.I prefer the latter.


library(reshape)
desc<-melt(mydata, measure.vars=c("WDI","R.WSP", "D.GST", "PRES",
"ATMP", "DEWP"),
           id.vars=c("X.YY","MM","DD"))
summary<-cast(desc, X.YY+MM+DD~variable, mean)









On 17 July 2016 at 06:22, Tom Mosca <tom at vims.edu> wrote:
> Hello Good Folk,
>
> My dataframe looks like this:
>> mydata
>      X.YY MM DD hh WDI R.WSP D.GST   PRES  ATMP  DEWP
> 1    2015  1  1  0 328   3.6   4.5 1028.0   3.8  -3.5
> 2    2015  1  1  1 300   2.1   2.7 1027.9   3.7  -4.4
> 3    2015  1  1  2 264   2.4   2.9 1027.7   3.6  -4.5
> 4    2015  1  1  3 230   4.1   4.5 1027.4   4.2  -3.8
> 5    2015  1  1  4 242   8.1   9.2 1026.6   4.4  -3.1
> 6    2015  1  1  5 262   9.3  10.1 1026.6   4.1  -3.8
> 7    2015  1  1  6 267   8.6   9.6 1026.3   4.2  -3.8
> 8    2015  1  1  7 264   9.3   9.9 1026.1   3.9  -2.8
> 9    2015  1  1  8 268   8.2   9.1 1026.1   3.5  -3.0
> 10   2015  1  1  9 272   8.8   9.6 1025.4   3.2  -3.3 …
>
> The first four columns are year, month, day, hour (0 – 23).  I wish to take the means of the next six columns (WDIR, WSPD, GST, PRES, ATMP and DEWP) by year, month and day.  That is, I want daily averages.
>
> Please help.  Thank you.
>
> Tom
>
>         [[alternative HTML version deleted]]
>
>
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-- 
Jianling Fan
樊建凌