Thank you!

On Tue, Mar 20, 2012 at 8:39 PM, David Winsemius <dwinsemius@comcast.net>wrote:

>
> On Mar 20, 2012, at 7:52 PM, Laura Rodriguez Murillo wrote:
>
>  Dear list,
>> I have a data frame where one of the columns are p values with scientific
>> notation mixed with regular numbers with decimals.
>>
>>> a=data frame
>>> a
>>>
>>     P     OR   N
>> 0.50 0.7500 237
>> 0.047 1.1030 237
>> 0.124 0.7742 237
>> 0.124 0.7742 237
>> 0.0080 1.1590 237
>> 0.50 0.7500 237
>> 4.5e-07 1.2 237
>> 5.6e-04 0.9 237
>>
>> when I try to do
>>
>>> pval=a$P/2
>>>
>>
>> R gives me an error saying "In Ops.factor(pval, 2) : / not meaningful for
>> factors"
>>
>
> It is a complete mystery to me that people don't believe the error
> messages.  a$P is a factor. Something you did created a factor (probably at
> data entry time), and you didn't realize it. You can change it to numeric
> with:
>
> a$P <-  as.numeric(as.character(a$P))
>
> --
>
> David Winsemius, MD
> West Hartford, CT
>
>

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