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How to read in data

4 messages · Mathieu Ros, Barry Rowlingson, Anne Piotet

Original
Mathieu Ros
# 
AP> Hello, I'm new to R and in the process of testing it My first
    AP> question: I fail to read in my data (ANSI toto.txt file, tab
    AP> separated)
    >> test <-read.table("toto.txt")
    AP>             Error in file(file, "r") : unable to open
    AP> connection In addition: Warning message: cannot open file
    AP> `toto.txt'
    >> test <- scan("C:\\toto.txt")
    AP>             Error in scan("C:\\toto.txt") : "scan" expected a
    AP> real, got "No_D"
    >> test <-scan("test.dat")
    AP>             Error in file(file, "r") : unable to open
    AP> connection In addition: Warning message: cannot open file
    AP> `toto.txt (and no, it is not read only or locked or whatever)
    AP> I use Windows 2000/XP

I think
read.table("C:\\toto.txt",header=TRUE)
will do the job : the message you got on your first and third attempts
means that you gave a wrong path to your file.
otherwise, read the help for read.table carefully (header and skip parameters).

    AP> second question...what are the size limits of statistical
    AP> files I can handle? I plan to analize plant datas (up to
    AP> 500'000 records, from which I will analize a restrictive set
    AP> of variates ) Even when broken down by some chracteristics,
    AP> the data to analize can have 50'000-100'000 records

    AP> Well thank for the help Anne
de rien ;)

regards,

--Mathieu
Barry Rowlingson
#
Anne Piotet wrote:
- that's because it didnt find the file in that location.
- that's because it did find the file, but there was the text "No_D" 
in it. scan() will only read numbers unless you tell it otherwise.
again, its not looking in c:\, so it doesn't find it. Funny how 
scan("test.dat") brings up an error about "toto.txt" :)

  R has a working directory which is where scan() and read.file() will 
start looking for files without a full path - type getwd() to see where 
that is at any time.

  You didnt try the other option:

   test <- read.table("c:\\toto.txt", sep='\t')

- I give a full path to toto.txt and tell it the columns are separated 
with tabs ('\t'). You may need other options - popular ones are as.is=T 
which keeps character variables as text rather than converting to 
categorical data (factors), and head=T if the first line of the file is 
a header with column names.

  If this works, then do names(test) and summary(test) to see what 
you've got.
Depends - whats the size of the machine you are using (and dont say 
its a small box that fits under my monitor). How much RAM and disk space 
does it have?

Baz
2 days later
Anne Piotet
# 
Thanks! yes it WORKS
Anne

----- Original Message -----
From: "Mathieu Ros" <mros at autan.toulouse.inra.fr>
To: "Anne Piotet" <Anne.Olga.Piotet at omsv.vd.ch>
Cc: <r-help at stat.math.ethz.ch>
Sent: Tuesday, July 15, 2003 4:58 PM
Subject: Re: [R] How to read in data
parameters).