Specifying colClasses in the read.csv

r csv read.csv
defoo picture defoo · May 10, 2010 · Viewed 177k times · Source

I am trying to specify the colClasses options in the read.csv function in R. In my data, the first column "time" is basically a character vector while the rest of the columns are numeric.

data <- read.csv("test.csv", comment.char="" , 
                 colClasses=c(time="character", "numeric"), 
                 strip.white=FALSE)

In the above command, I would want R to read in the "time" column as "character" and the rest as numeric. Although, the "data" variable did have the correct result after the command completed, R returned the following warnings. I am wondering how I could fix these warnings? 

Warning messages:
 1: In read.table(file = file, header = header, sep = sep, quote = quote,  :
    not all columns named in 'colClasses' exist
 2: In tmp[i[i > 0L]] <- colClasses :
    number of items to replace is not a multiple of replacement length

Derek

Answer

Etienne picture Etienne · Nov 18, 2011

You can specify the colClasse for only one columns.

So in your example you should use:

data <- read.csv('test.csv', colClasses=c("time"="character"))

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