[R] Read data from .csv file as a matrix

Erik Iverson eriki at ccbr.umn.edu
Wed May 5 21:38:04 CEST 2010


Hello,

> I have a csv file that contains weather observation (rows) by days (in
> columns). 
> 
> I open using: 
> 
>> temp = read.csv("Weather.csv", sep=",") 
> 
> and read: 
> 
>              X X1.Jan X2.Jan X3.Jan X4.Jan 
> 1          Min      2      3      4      1 
> 2          Max      6     10      8      6 
> 3 Forecast Min      3      1      1      3 
> 4 Forecast Max      8      7      4      9 
> 
> If I type 
> 
> mean(temp[2,2:3]) 
> 
> I get 
> 
> X1.Jan X2.Jan 
>      6     10 
> 
> The same command on 
> 
>> y = matrix(1:21, ncol=7) 
> 
>> mean(y[2,2:3]) 
> [1] 6.5 
> 
> Works because the data is in a matrix. I believe R stores the data from the
> csv file as a data.frame with these annoying headers. So how do I convert
> the data from my csv file into a matrix? 
> 
> I tried as.matrix but it did not help. 
> 

Giving us a reproducible example with ?dput output from your temp object 
would most likely help us solve the problem very quickly.



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