[R] Problems with read.table

[Heberto Ghezzo]

Hi I am using R65.1 in Windows 95
I have a CSV file from Excell
> 
a<-read.table("c:/heberto/mgc/tst.csv",header=T,sep=",")
> attach(a)
> a
  manolo  fvcpp  fevpp fvvcpp   tlcpp    rvpp  rvtlpp plmaxpp
1     1  99.28  97.67  98.38   91.14   102.9  111.25  117.64 
2     1  86.97  68.56  78.89   94.60  112.34  118.53   159.20
3     1  81.12  71.76  88.37   89.16  114.17  126.86   60.71 
4     1  98.12  86.05  87.73  102.34  127.41  123.05  102.13 
5     1  90.50  80.87  89.47   85.60   93.27  107.35   86.03 

--This is correct

> mean(fvcpp)
Error: "sum" not meaningful for factors
> fvcpp
[1] 99.28  86.97  81.12  98.12  90.50 
Levels:  81.12  86.97  90.50  98.12  99.28  

-- it reads the columns as factors and not as numeric

>  rm(a)
> a<-read.table("c:/heberto/mgc/tst.csv",header=T,sep=",",as.is=F)
> attach(a)
> mean(fvcpp)
Error: "sum" not meaningful for factors
> ls()
[1] "a"
> rm(a)
> a<-read.table("c:/heberto/mgc/tst.csv",header=T,sep=",",as.is=T)
> attach(a)
> mean(fvcpp)
Error in sum(..., na.rm = na.rm) : invalid "mode" of argument
>

-- so now, how can I read the file as numeric vectors?

> fvcpp
[1] "99.28 " "86.97 " "81.12 " "98.12 " "90.50 "
> fvcpp<-as.numeric(fvcpp)
> fvcpp
[1] 99.28 86.97 81.12 98.12 90.50
> mean(fvcpp)
[1] 91.198
>

-- this is obviously not the way to do it, for each variable
change it into numeric.
 
Can somebody tell me what I am doing wrong?, I used to follow the same 
procedure a<-read.table(...  attach(a)  and have all my variables as 
vectors with or without NA's .
This file has no NA's is all complete.
Thanks.
..
R. Heberto Ghezzo  Ph.D.
Meakins-Christie Labs
McGill University
Montreal - Canada
heberto at meakins.lan.mcgill.ca
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