Question

I have 2 columns of data with numerical values as follows which is tab delimited format:

Si1     Si2

8,99691 7,495936
7,7164173   8,092645
4,4428697   4,298263
7,4302206   7,189521
5,897344    5,316047
. 
.
.

To calculate correlation between these I wrote R code as follows:

int<-read.table("data.txt",sep="\t",head=TRUE)
attach(int)
cor(int$Si1,int$Si2)

But it shows error as follows:

Error in cor(int$Si1,int$Si2) : 'x' must be numeric

Can anybody tell me how to solve this?

Answer 1

To calculate a correlation between two vectors they must be numeric (numbers). You have commas in your data and so they are not numeric.

Are they meant to be there? This works fine:

x<-c(1,2,3,4,5)
y<-c(1,2,3,4,5)
cor(x,y)

returns [1] 1