[R] R - Array data loop selection

[David Winsemius]

On Feb 4, 2012, at 8:29 PM, dengyu19901102 wrote:

> i want to select June, July and August data from the 3D array  
> (`ssta_sst`,
> 360*180*362).
>
> the loop works but the output of ssta_winter has the identical  
> values for
> `ssta_winter[,,i]`.seen below. I have set it up as an array of  
> (360,180,29).
>
> I think the problem is the variable `temp`, i want to define it as  
> an array
> first but i don't know what size it should be (360,180,3) or  
> (360,180,3*29)
> and how to keep a loop counter in `temp` when it passes down to  
> finding mean
> stage?
>

You need to post the results of str(ssta_sst)



>
>
>    ssta_winter = array( data=NA, dim = c(360,180,29))
>    temp = array( data=NA, dim = c(360,180,3))
>
>    for (yr in 1982:2010) {
>    	temp <- ssta_sst[,,year_sst==yr & (month_sst>=6 & month_sst<=8)]

# As a devugging step you could run this for one of two years and  
insert:

           print(str(temp))

# to make sure you are not having problems with that assignment
#--
#David.
>    	for (i in 1:360) {
>    		for (j in 1:180) {
>    			ssta_winter[i,j,] <- mean(temp[i,j,])
>    		}
>    	}
>    }
>
>> for (i in 1:29){
>    + print(ssta_winter[180,166,i])
>    + }
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>    [1] 0.2222583
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/R-Array-data-loop-selection-tp4358282p4358282.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT