Taking mean of 3 cols in data frame : error

I exactly know my problem. The read.table by default reads my data
from few columns as factors/character type.  Can you please give me an
example of how to force it to read these columns as numbers. I dont
see example of how to use (as.is)

Thanks!
-Abhi

On Sat, Jan 30, 2010 at 12:34 AM, Abhishek Pratap
<abhishek.vit at gmail.com> wrote:

I see what is happening here. When I am reading the data frame values
from a csv file, they are not read as numerics.

_A

On Sat, Jan 30, 2010 at 12:29 AM, Abhishek Pratap
<abhishek.vit at gmail.com> wrote:

Hi All

I am seeing quite a silly thing for which I dont have much of
explanation. I want to take per row mean of 3 columns of a data  
frame.
 What I am getting is  all NA in the result. Here is what I am doing


apply(a[,1:3],1,mean)

I get warnings.

 In mean.default(newX[, i], ...) :
 argument is not numeric or logical: returning NA

I am not sure how it thinks the values are not numeric. May be I  
had a
long day and not able get something fairly obvious.

==========
summary(a)

 animal1_wt             animal2_wt                               
animal3_wt
 0         : 5448          0         : 5295                
0         :
5501
 0.232266  :    7          0.17356   :    5            
6.22424   :    6
 1.05487   :    6          0.00630758:    4            
0.0395818 :    5
 0.258336  :    5          0.0131442 :    4            
4.14949   :    5
 0.372308  :    5          0.0143924 :    4            
0.00964998:    4
 0.00926343:    4          0.017208  :    4            
0.0172297 :    4
 (Other)   :15696          (Other)   :15855           (Other)   : 
15646