[R] How to extract Friday data from daily data.

[thornbird]

Hi thanks for quick reply. I am new to using R and still tried to figure out
how to use Zoo package. 

Here is the code I have so far: 

library(zoo)

colClasses <- c("NULL", "character", "character", "numeric", "character",
"character", "NULL")

col.names <- c(NA, "webpage", "item", "value", "day", "date", NA)

# z <- read.zoo("myfile.dat", skip = 1, index = as.list(1:6),
z <- read.zoo("C:\\Users\\Kevin\\Desktop\\testdata.csv", sep = ",", skip =
1, index = as.list(1:6),
        format = "%d/%m/%Y", col.names = col.names,
        aggregate = function(x) tail(x, 1), colClasses = colClasses)


# extract all Thursdays and Fridays
z45 <- z[format(time(z), "%w") %in% 4:5,]

# keep last entry in each week
# and show result on R console
z45[!duplicated(format(time(z45), "%U"), fromLast = TRUE), ]



I attached a reproducible dataset in excel and I hope to get the results as
follows. It would be great if I can get all days in Friday format as you
suggested in the second approach the first time. 

Again your time and help is appreciated!
http://r.789695.n4.nabble.com/file/n3031420/testdata.csv testdata.csv 



webpage	item	value	        day	date	       time
MattDamon	fans	642045	Thu	11-Jun-09	22:11:33
MattDamon	fans	765057	Fri	19-Jun-09	12:37:09
MattDamon	fans	899900	Sat	27-Jun-09	12:40:36  (no Fri or Thu, so I chose
Sat)
MattDamon	views	642045	Thu	11-Jun-09	22:11:33
MattDamon	views	765057	Fri	19-Jun-09	12:37:09
MattDamon	views	887195	Fri	26-Jun-09	13:36:12
AngieeJolie	fans	642045	Thu	11-Jun-09	22:11:33
AngieeJolie	fans	765057	Fri	19-Jun-09	12:37:09
AngieeJolie	fans	887195	Fri	26-Jun-09	13:36:12
AngieeJolie	views	642045	Thu	11-Jun-09	22:11:33
AngieeJolie	views	765057	Fri	19-Jun-09	12:37:09
AngieeJolie	views	887195	Fri	26-Jun-09	13:36:12

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