I have hundreds of csv files (zoo objects in R) with 2 columns:
"Index","pp"
1951-01-01,22.9
1951-01-02,4.3
1951-01-03,4.6
I want the second column to have the name of each file. For example, when a filename is 02O_zoo.csv I would like the second column to be "02O" instead of "pp". Is there an automatic way of doing this?
Thanks
(1) From files read.zoo can take a character vector of file names as its first argument so:
# create test files Lines <- '"Index","pp" 1951-01-01,22.9 1951-01-02,4.3 1951-01-03,4.6' cat(Lines, file = "testzoo01.csv") cat(Lines, file = "testzoo02.csv") # read.zoo reads the files named in Filenames and merges them library(zoo) Filenames <- dir(pattern = "testzoo.*csv") z <- read.zoo(Filenames, sep = ",", header = TRUE) which gives this:
> z testzoo01.csv testzoo02.csv 1951-01-01 22.9 22.9 1951-01-02 4.3 4.3 1951-01-03 4.6 4.6 It would be possible to modify the names further if desired by placing names on the Filenames variable, e.g. names(Filenames) <- gsub("testzoo|.csv", "", Filenames), or by modifying the names of the result, e.g. names(z) <- gsub("testzoo|.csv", "", names(z))
(2) From zoo Objects. If they have been read in previously then try this:
# create test objects using Lines and library() statement from above testobj1 <- testobj2 <- read.zoo(textConnection(Lines), header = TRUE, sep = ",") # merge them into a single zoo object zz <- do.call(merge, sapply(ls(pattern = "testobj.*"), get, simplify = FALSE)) which gives this:
> zz testobj1 testobj2 1951-01-01 22.9 22.9 1951-01-02 4.3 4.3 1951-01-03 4.6 4.6 The names of zz could be modified further as in the discussion above.
