[R] Help with apply()

[Nathan S. Watson-Haigh]

On 8/02/2010 2:08 PM, David Winsemius wrote:
> On Feb 7, 2010, at 8:26 PM, Nathan S. Watson-Haigh wrote:
>
>    
>> I have a 2 column data.frame:
>>
>>      
>>> d[1:5,]
>>>        
>>   a b
>> 1    80015     C
>> 2    80016     B
>> 3    80023     C
>> 4    80062     B
>> 5    80069     B
>>
>> I want to apply a function across each row:
>>
>>      
>>> for(i in 1:nrow(d)) {
>>>        
>> +    myFun(con, d[i,]$a, d[i,]$b)
>> + }
>>
>> How do I do this using apply()? I'm unsure how to tell apply() to
>> pass data from columns a and b for a given row as arguments to the
>> function myFun().
>>      
> apply(d, 1, function(x) myFun(x[1], x[2]) )
>
> The reason you cannot use the "$" operator is that the row is passed
> to the function as a vector, rather than as a list.
>
>    

Thanks for the info, it was ever so slightly out......But for anyone 
else who might read this, the full working code of my example was as 
follows:

apply(d, 1, function(x) myFun(con, x[1], x[2]))

Cheers,
Nathan

--------------------------------------------------------
Dr. Nathan S. Watson-Haigh
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CSIRO Livestock Industries
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