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annual maximum value
3 messages · CJ Rubio, Gabor Grothendieck
Try this:
Lines <- textConnection("10/1/1989,2410
+ 10/2/1989,2460 + 10/3/1989,2890 + 12/31/2005,5730")
library(zoo) library(chron) z <- read.zoo(Lines, header = FALSE, sep = ",", FUN = chron) aggregate(z, floor(as.numeric(as.yearmon(time(z)))), max)
1989 2005 2890 5730 See ?read.zoo, ?aggregate.zoo, ?as.yearmon, the 3 vignettes in the zoo package and R News 4/1.
On Mon, Feb 16, 2009 at 10:11 PM, CJ Rubio <cjrubio at kongju.ac.kr> wrote:
hi everyone! hope you can help me here. i am a new R user. what i am trying to do is to find the maximum annual discharge from a daily record. i have a data.frame which includes date and the discharge. somewhat like this.. 10/1/1989 2410 10/2/1989 2460 10/3/1989 2890 ... ... ... 12/31/2005 5730 i have been browsing through the archives and fount out about the aggregate function and the zoo package. here's one of the codes i've tried DF <- read.table(data[i], sep =",") ##i have several stations to assimilate Date <- as.Date(as.character(DF[,3]), "%m/%d/%Y") #the date is at the 3rd column, obviously library(zoo) z <- aggregate(zoo(DF[,4]), cut(Date, "y"), max) max.discharge <- coredata(z) date <- time(z) the result should somehow look like this 11/21/1926 32600 4/24/1927 66500 ... ... .. 4/26/2005 111000 thanks for your time reading my questions,, any suggestions will be truly appreciated... -- View this message in context: http://www.nabble.com/annual-maximum-value-tp22049205p22049205.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]]
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thank you very much for your reply. i studied the code you gave me and tried to make adjustments to fit the requirements that i need, thank you again.. i used the following codes:
m <- read.table("D:/documents/5 stations/01014000.csv", sep =",")
z <- zoo(m[,4],as.Date(as.character(DF[,3]), "%m/%d/%Y"))
x <- aggregate(z, cut(time(z),"y"), max)
i got the maximum values right using coredata(), my question now is, how can i call for the complete date (yyyy-mm-dd) and the year (yyyy) when the maximum observation for that year was observed?
CJ Rubio wrote:
hi everyone! hope you can help me here. i am a new R user. what i am trying to do is to find the maximum annual discharge from a daily record. i have a data.frame which includes date and the discharge. somewhat like this.. 10/1/1989 2410 10/2/1989 2460 10/3/1989 2890 ... ... ... 12/31/2005 5730 i have been browsing through the archives and fount out about the aggregate function and the zoo package. here's one of the codes i've tried DF <- read.table(data[i], sep =",") ##i have several stations to assimilate Date <- as.Date(as.character(DF[,3]), "%m/%d/%Y") #the date is at the 3rd column, obviously library(zoo) z <- aggregate(zoo(DF[,4]), cut(Date, "y"), max) max.discharge <- coredata(z) date <- time(z) the result should somehow look like this 11/21/1926 32600 4/24/1927 66500 ... ... .. 4/26/2005 111000 thanks for your time reading my questions,, any suggestions will be truly appreciated...
View this message in context: http://www.nabble.com/annual-maximum-value-tp22049205p22051398.html Sent from the R help mailing list archive at Nabble.com.