annual maximum value

Lines <- textConnection("10/1/1989,2410

library(zoo)
library(chron)
z <- read.zoo(Lines, header = FALSE, sep = ",", FUN = chron)
aggregate(z, floor(as.numeric(as.yearmon(time(z)))), max)

 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...



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