[R] Count number in r

[John Wasige]

Dear all,

I am kindly requesting for help on how I can count pixels with value less
and equal to -0.08 for a raster stack.

Thanks for your help

John

On Tue, May 19, 2015 at 5:57 PM, John Kane <jrkrideau at inbox.com> wrote:

> And another approach just for the heck of it.
>
> library(plyr)
>
> # where dat1 is your data
> dd1  <-  subset(dat1, Rain >= .01)
>
> dd1$Year  <-  as.factor(dd1$Year)
> dd1$Month  <-  as.factor(dd1$Month)
>
> count (dd1, .(Year, Month))
>
> John Kane
>
> Kingston ON Canada
>
>
> > -----Original Message-----
> > From: hafizuddinarshad21 at gmail.com
> > Sent: Tue, 19 May 2015 03:10:32 -0700
> > To: r-help at r-project.org
> > Subject: [R] Count number in r
> >
> > Dear R users,
> >
> > Could someone help me on this? I have this kind of data set:
> >
> > structure(list(Year = c(1971L, 1971L, 1971L, 1971L, 1971L, 1971L,
> > 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L,
> > 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L,
> > 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L,
> > 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L, 1971L,
> > 1971L, 1971L), Month = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
> > 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
> > 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
> > 2L, 2L, 2L), Rain = c(58.9, 74.6, 17.7, 7.8, 1.2, 1, 5.3, 0.7,
> > 1.2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> > 0, 10.4, 17.5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)), .Names =
> > c("Year",
> > "Month", "Rain"), class = "data.frame", row.names = c(NA, -44L
> > ))
> >
> > I want to count data in "Rain" that is greater and equal to 0.1 mm
> > according to their "Month" and "Year". I have used this code, but it
> > seems
> > so wrong.
> >
> > raindat <- read.csv('my data set',header=TRUE)
> > yearcorr<-min(raindat$Year)-1
> > years<-unique(raindat$Year)
> > rainmonth<-as.data.frame(matrix(0,nrow=2,ncol=12))
> > for(year in years) {
> >   for(month in 1:12) {
> >     if(any(raindat$Year==year&raindat$Month==month))
> >       rainmonth[year-yearcorr,month]<-
> >       length((which(raindat$Rain >=
> > 0.1))[raindat$Year==year&raindat$Month==month])
> >   }
> > }
> > rownames(rainmonth)<-years
> > names(rainmonth)<-month.abb
> > rainmonth
> >
> > Thank you so much.
> >
> >
> > Arshad
> >
> >       [[alternative HTML version deleted]]
> >
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> > and provide commented, minimal, self-contained, reproducible code.
>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
John Wasige
"Birds born in a Cage think Flying is an illness."

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