R help - Mar 2009 - Eliminate Factors from Data Frame

Hi,
   I formed a 49 by 3 data frame by reading in a text file using read.table(),
and combining it with a matrix that I made by using unlist() on a list of
character strings. I would like to do some simple arithmetic operations on the
elements in the data frame columns (e.g. column 3/column2) but the values in the
data frame are stored as factors and using stringsAsFactors=FALSE did not work.
I get this error when doing arithmetic operations:
In Ops.factor(dataframe$col3, dataframe$col2) : / not meaningful for factors
Is there a way to store these values not as factors or convert them to numeric
values? Or a way to do operations on factors in data frames? I know R has I()
but that didn't help in this case. Thanks so much.


      
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It's in the R-FAQ. I can't remember it's 7.20 or 7.35 but it's
in that
general area.

-- 
David Winsemius


On Mar 4, 2009, at 3:38 PM, Bob Roberts wrote:
> Hi,
>   I formed a 49 by 3 data frame by reading in a text file using  
> read.table(), and combining it with a matrix that I made by using  
> unlist() on a list of character strings. I would like to do some  
> simple arithmetic operations on the elements in the data frame  
> columns (e.g. column 3/column2) but the values in the data frame are  
> stored as factors and using stringsAsFactors=FALSE did not work. I  
> get this error when doing arithmetic operations:
> In Ops.factor(dataframe$col3, dataframe$col2) : / not meaningful for  
> factors
> Is there a way to store these values not as factors or convert them  
> to numeric values? Or a way to do operations on factors in data  
> frames? I know R has I() but that didn't help in this case. Thanks  
> so much.
>
>
>
> 	[[alternative HTML version deleted]]
>
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