Roc1<-plot.roc(tlog$NSSI, tlog$premodel, main="ROC", percent=TRUE, col="black",lty=1,lwd = 2)
Roc2<-lines.roc(valdata$NSSI, valdata$premodel, main="ROC", percent=TRUE, col="grey",lty =2,lwd = 2)
legend("bottomright", legend=c("Roc1-AUC=0.808", "Roc2-AUC=0.722"), col=c("black", "grey"), lty=c(1,2),lwd = c(2,2))