カンマ区切りで表示したい時はformatCを使う。
http://stackoverflow.com/questions/1581232/adding-commas-into-number-for-output
formatC(100000, format="d", big.mark=',')
http://stackoverflow.com/questions/1581232/adding-commas-into-number-for-output
formatC(100000, format="d", big.mark=',')