
Dear Helpers,

I wrote a simple function to standardise variables if they contain more than one value. If the elements of the variable are all identical, then I want the function to return zero.

When I submit variables whose elements are all identical to the function, it returns not zero, but NaNs.

zt=function(x){if (length(table(x)>1)) y=(x-mean(x))/sd(x) else if (length(table(x)==1)) y=0; return(y)}

zt(c(1:10))
#[1] -1.4863011 -1.1560120 -0.8257228 -0.4954337 -0.1651446  0.1651446  0.4954337  0.8257228  1.1560120  1.4863011

zt(rep(1,10))
#[1] NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN

Would you be so kind as to point out what I am doing wrong, here? How can I obtain zeros from my function, instead of NaNs? (I obtain NaNs also if I set the function to zt=function(x){if (length(table(x)>1)) y=(x-mean(x))/sd(x) else if (length(table(x)==1)) y=rep(0, length(x)); return(y)} ).

Thanks, in advance, for your help,

Jonathan Williams
 		 	   		   		 	   		  
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