[R] Removing NAs from matrix

[Rui Barradas]

Hello,

Your code corrected would be


mean.matrix[, 1] <- apply(mat, 1, mean, na.rm = TRUE)

(No need for the for loop).
Even better would be to avoid loops and use the base R function ?rowMeans.

mean.matrix[, 1] <- rowMeans(mat, na.rm = TRUE)

Hope this helps,

Rui Barradas

Em 01-12-2013 12:16, Amie Hunter escreveu:
> Hello R users,
>
> I'm new to R so apologies if this question seems simple. I have a matrix which is 35000 columns by 35000 rows and I’m wanting to work out the mean of each row. I've tried using the code below on a smaller version of the matrix, but receive an error:
>
>> mat
>        [,1]      [,2] [,3]      [,4]       [,5]      [,6]      [,7]      [,8]      [,9]     [,10]     [,11]
>   [1,]   NA 0.3904762  0.2 0.4285714 0.04761905        NA        NA        NA        NA        NA        NA
>   [2,]   NA        NA  0.2 0.2000000 0.23809524 0.2190476        NA        NA        NA        NA        NA
>   [3,]   NA        NA   NA 0.5047619 0.27619048 0.2952381 0.1428571        NA        NA        NA        NA
>   [4,]   NA        NA   NA        NA 0.42857143 0.3714286 0.3333333 0.2190476        NA        NA        NA
>   [5,]   NA        NA   NA        NA         NA 0.8666667 0.6761905 0.4857143 0.6571429        NA        NA
>   [6,]   NA        NA   NA        NA         NA        NA 0.6190476 0.4285714 0.6761905 0.4857143        NA
>   [7,]   NA        NA   NA        NA         NA        NA        NA 0.6952381 0.6380952 0.6000000 0.2571429
>   [8,]   NA        NA   NA        NA         NA        NA        NA        NA 0.6761905 0.6000000 0.1809524
>   [9,]   NA        NA   NA        NA         NA        NA        NA        NA        NA 0.6190476 0.3142857
> [10,]   NA        NA   NA        NA         NA        NA        NA        NA        NA        NA 0.5809524
> [11,]   NA        NA   NA        NA         NA        NA        NA        NA        NA        NA        NA
>> mean.matrix <- matrix(ncol=1, nrow=10)
>> for (i in mat)
> + mean.matrix[,i] <- apply(mat,1,mean)
> Error: NAs are not allowed in subscripted assignments
>
> I have come across the na.omit() function however this completely removes the row. Is there any way I can either remove all the NAs from the matrix or pull out the values of each row to work out the mean?
>
> Thanks,
>
> Amie 		 	   		
> ______________________________________________
> 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.
>