Trying to write csv file to R variable

Question

My intention is to format a simple matrix in csv format. As I need to further process the formatted lines, I don't want to write the formatted string to a file.

I already tried using textConnection, which seems to be the right approach.

m<-matrix(c(1,2,3,4), nrow=2)
result<-write.csv(m, file=textConnection(csvData), row.names=FALSE, col.names=FALSE)

I'm expecting csvData to contain the contents of the formatted csv (file) as a vector containing the lines.

I get the error:

Error in textConnection(csvData) : invalid 'text' argument

What is the proper usage of textConnection?

Revised question

After some trying and cleaning all variables I ended up with

rm(list = ls())
m<-matrix(c(1,2,3,4), nrow=2)
result<-write.csv(m, file=textConnection("csvData", "w"), row.names=FALSE, col.names=FALSE)

This produces at least no errors, but I ended with a warning that col.names are ignored. The content of csvData is also not what I expected

> csvData
[1] "\"V1\",\"V2\"" "1,3"           "2,4"

How to remove the header?

My solution

After trying I found, that write.csv should be replaced by write.table.

rm(list = ls())
m<-matrix(c(1,2,3,4), nrow=2)
result<-write.table(m, file=textConnection("csvData", "w"), row.names=FALSE, col.names=FALSE, sep=";")

Does write.csv(m, "mymatrix.csv") generate the desired output? Check it via read.csv("mymatrix.csv"). — Manuel Bickel
– Manuel Bickel, Commented Dec 8, 2017 at 10:24
Yes, but I don't want the header and row names in the output file. I thought write.csv(m, "mymatrix.csv", row.names=FALSE, col.names=FALSE) should do it, right? — Aleph0
– Aleph0, Commented Dec 8, 2017 at 10:27
But col.names is ignored, so why write.csv has a paramater col.names, which is just ignored? — Aleph0
– Aleph0, Commented Dec 8, 2017 at 10:28

nghauran · Accepted Answer · 2017-12-08 10:39:45Z

1

Try write.csv() from MASS

MASS::write.matrix(m, file = textConnection("csvData", "w"), sep = ";")

edited Dec 8, 2017 at 10:39

answered Dec 8, 2017 at 10:30

nghauran

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2 Comments

Aleph0 Over a year ago

Thanks, but I don't want to write to a file. I wanted to write to vector containing the lines of the file. I already found a solution. Thanks for your efforts.

Aleph0 Over a year ago

Hilarious. Many thanks, even though I already found a working solution for myself.

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