[R] change cell values

[Rui Barradas]

Hello,

It's not working because you are changing mat1 before the second 
condition is evaluated, and so mat1 is full of NA values. Try the following.



tmp <- mat1  # Make a copy
tmp[mat1 < 1 & mat2 < 1] <- NA  # And change that copy
mat2[mat1 < 1 & mat2 < 1] <- NA
mat1 <- tmp
rm(tmp)


Hope this helps,

Rui Barradas

Em 03-07-2013 22:27, JiangZhengyu escreveu:
>
>
>
> Dear R experts,
>
> I have two  matrices (mat1 & mat2) with the same dimension & the cells (row and column) are corresponding to each other.
>
> I want to change cell values to NA given values of the corresponding cells in mat1 and mat2 are both <1.
>
> E.g. both mat1[2,3] and mat2[2,3] are <1, I will put mat1[2,3]=NA, and mat2[2,3]=NA; if either mat1[2,3]>=1 or  mat2[2,3]>=1, I will save both cells.
>
> I tried the code, but not working. Could anyone can help fix the problem?
>
> mat1[mat1<1&mat2<1]=NA
> mat2[mat1<1&mat2<1]=NA
>
>
>> mat1=matrix(rnorm(12),3)
>> mat2=matrix(rnorm(12),3)
>> mat1
>             [,1]       [,2]       [,3]       [,4]
> [1,] -1.3387075 -0.7142333 -0.5614211  0.1846955
> [2,] -0.7936087 -0.2215797 -0.3686067  0.7328731
> [3,]  0.6505082  0.1826019  1.5577883 -1.5580384
>> mat2
>             [,1]       [,2]       [,3]       [,4]
> [1,]  0.4331573 -1.8086826 -1.7688123 -1.4278934
> [2,] -0.1841451  0.1738648 -1.1086942  1.3065109
> [3,] -1.0827245 -0.4143808 -0.6889405  0.4046203
>
>   		 	   		
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>