[R] Assignment problems

[David Winsemius]

On Apr 23, 2012, at 5:21 PM, R. Michael Weylandt wrote:

> That's not the ifelse() that's the for loop returning NULL
> (everything's a function!). If you put the assignment inside you'll
> get expected behavior.
>
> x <- (for(i in 1:5) i) # Strange
> for(i in 1:5) x<- i # Normal (but notice you only get the last value
> because previous ones are overwritten)
>

Better would be to avoid the for-loop altogether. And phillip03 should  
note: The for-loop does not create an environment where column names  
are interpreted as object names and I'm guessing that 'avgflowEMU' is  
not an object but rather a column name.

Depending on the unstated goal (and quite a few other unstated  
concerns), something like this might make more sense:

EMU1993<-sum( data[ data$year==1993,  "avgflowEMU" ], na.rm=TRUE)

phillip03: please stop using 'data' as an object name. It is also the  
name of an R function.
-- 
David.

> Michael
>
> On Mon, Apr 23, 2012 at 4:26 PM, phillip03  
> <phillipbrigham at hotmail.com> wrote:
>> Hi
>>
>>> EMU1993<-(for (i in 1:nrow(data)){
>> +       ifelse(year==1992,sum(avgflowEMU),0)
>> +       })
>>
>>> EMU1993
>> NULL
>>

David Winsemius, MD
West Hartford, CT