mydata <- mydata[,c("PS","TS","imposition","Lrsuccess","Rsucess",
+ "IO","Msenders","tcosts","CR","TL","Ally","CI",
+ "GDP","US","threatonly" )
+ ]
Error in `[.data.frame`(mydata, , c("PS", "TS", "imposition", "Lrsuccess", :
undefined columns selected