[R] Extracting part of a factor

[KMNanus]

When I do that, I get "Error in `$<-.data.frame`(`*tmp*`, "site", value = integer(0)) : 
  replacement has 0 rows, data has 6”

The data frame has 6 rows.

Ken
kmnanus at gmail.com
914-450-0816 (tel)
347-730-4813 (fax)



> On Mar 3, 2016, at 4:52 PM, Hervé Pagès <hpages at fredhutch.org> wrote:
> 
> Hi,
> 
> On 03/03/2016 12:18 PM, KMNanus wrote:
>> I have a factor variable that is 6 digits and hyphenated.  For example, 001-014.
>> 
>> I need to extract the first 3 digits to a new variable using mutate in dplyr - in this case 001 - but can’t find a function to do it.
>> 
>> substr will do this for character strings, but I need the variable to remain as a factor.
> 
> What prevents you from calling as.factor() on the result to turn it
> back into a factor?
> 
> H.
> 
>> 
>> Is there an R function  or workaround to do this?
>> 
>> 
>> Ken
>> kmnanus at gmail.com
>> 914-450-0816 (tel)
>> 347-730-4813 (fax)
>> 
>> 
>> 
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> 
> -- 
> Hervé Pagès
> 
> Program in Computational Biology
> Division of Public Health Sciences
> Fred Hutchinson Cancer Research Center
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> 
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