[R] Help with read.csv

[David Wolfskill]

On Wed, Mar 09, 2011 at 04:32:29PM -0600, Giovanni Petris wrote:
> 
> Hello,
> 
> I have a file that looks like this:
> 
> Date,Hour,DA_DMD,DMD,DA_RTP,RTP,,
> 1/1/2006,1,3393.9,3412,76.65,105.04,,
> 1/1/2006,2,3173.3,3202,69.20,67.67,,
> 1/1/2006,3,3040.0,3051,69.20,77.67,,
> 1/1/2006,4,2998.2,2979,67.32,69.10,,
> 1/1/2006,5,3005.8,2958,65.20,68.34,,
> 
> where the ',' is the separator and I tried to read it into R, but...
> 
> > y <- read.csv("Data/Data_tmp.csv", header = FALSE, skip = 1,
> +               colClasses = c("character", "int", rep("double", 4)),
> +               col.names = c("Date","Hour","DA_DMD","DMD","DA_RTP", "RTP"),
> +               flush = TRUE)
> Error in read.table(file = file, header = header, sep = sep, quote = quote,  : 
>   more columns than column names
> 
> count.fields() gives me 8 fields per line, so I tried other variations,
> like the following, with two fictitious extra fields, but...
>...
> Error in methods::as(data[[i]], colClasses[i]) : 
>   no method or default for coercing "character" to "int"
> 
> Could anybody please tell me what I am doing wrong and how I could read
> my data into R?

I copied the data locally, then I read it using:

> y <- read.csv("Data_tmp.csv", header = TRUE, colClasses = c("character", "integer", rep("double", 4), "NULL", "NULL"))

which yields:

> y
      Date Hour DA_DMD  DMD DA_RTP    RTP
1 1/1/2006    1 3393.9 3412  76.65 105.04
2 1/1/2006    2 3173.3 3202  69.20  67.67
3 1/1/2006    3 3040.0 3051  69.20  77.67
4 1/1/2006    4 2998.2 2979  67.32  69.10
5 1/1/2006    5 3005.8 2958  65.20  68.34
> 

Is that what you had in mind?

Issues I tried to address:
* The class is "integer", not "int".
* I used "NULL" class to refer to columns that are to be skipped.
* I made use of the headers, rather than skipping them & re-coding their
  content in the read.csv() invocation.

Peace,
david
-- 
David H. Wolfskill				r at catwhisker.org
Depriving a girl or boy of an opportunity for education is evil.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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