[R] How to extract Friday data from daily data.
thornbird
huachang396 at gmail.com
Mon Nov 8 03:08:55 CET 2010
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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