[R] readHTMLTable function - unable to find an inherited method ~ for signature "NULL"

Hi R experts, I have been playing with library(XML) recently and found out that readHTMLTable workls flawlessly for some website, but it does give me an error like below ... Error in function (classes, fdef, mtable) : unable to find an inherited method for function "readHTMLTable", for signat

[R] pairwise correlation of many samples

Dear list, I have a csv file like below, and I have similar 150 files (responses from 150 samples) in a folder. I’d like to get the mean score of pairwise correlation score among 150 respondents by hour(0~20hour). All I can think of is bring up two files and get the pairwise correlation score