cor shows only NA or 1 for correlations - Why?

Question

I\'m running cor() on a data.framewith all numeric values and I\'m getting this as the result:

       price exprice...
price      1         


        

Answer 1

The NA can actually be due to 2 reasons. One is that there is a NA in your data. Another one is due to there being one of the values being constant. This results in standard deviation being equal to zero and hence the cor function returns NA.