thanks,
   
  can I ask another basic question?
  I have a matrix (10000 X 6). 10000 rows and 6 columns.
  I want to remove rows that have sd(col1, col2,col3) <1 or sd(col4,col5,col6) <1.
  what is the simple way?
   
  Yu
  
Duncan Murdoch <murdoch@stats.uwo.ca> wrote:
  On 16/04/2008 7:33 PM, Yuan Jian wrote:
> Hello,
> I have a matrix, I want to change value to 0 when a element in the matrix has less than 10.
> do you know how to do it without using loops?

A[A < 10] <- 0

Remember that matrices are just vectors with dimensions, so you can 
index one like a vector.

Duncan Murdoch


       
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