Dear R-Help Members,
I am trying to read and analyse a set of 100 csv files.
I need work only on some columns in each of those, so I decided to use
a for loop, isolate the
column in each file to work on, but then an error mesage appear:
"undefined columns selected"
Here is my code:
setwd("F:/Data/")
a<-list.files()
for (x in a) {
u<-read.csv(x, header=T, sep=",", check.names=FALSE)
#it give me the same problem using read.table
h<-u[,2]
}
Error in `[.data.frame`(u, , 2) : undefined columns selected
It does not give me any problem selecting ane entire row (e.g. u[2,])
or a single value (e.g. [5,2])
If I try to select a column after the for loop I does not show any
problem, e.g.:
a<-list.files()
for (x in a) {
u<-read.csv(x, header=T, sep=",", check.names=FALSE)
}
h<-u[,2]
I would appreciate any suggestion or pointer to solve the problem or
to do the same thing in a different way.
Thanks for your consideration
--
Michela Leonardi
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