Dear R Studio Community,

I am trying to plot 2 ROC curves in one graph to nicely compare them.

I used the "cutpointr" package and I don't know how to merge the 2 results.

```
y <- data[ , c( " pnf " , " lac " )]
roc1 <- cutpointr( data = y , x= lac , class = pnf ,
method = maximize_metric, metric = sum_sens_spec, na.rm = FALSE)
summary(roc1)
plot(roc1)
y <- data[ , c( " aed " , " lac " )]
roc2 <- cutpointr( data = y , x= lac , class = aed ,
method = maximize_metric, metric = sum_sens_spec, na.rm = FALSE)
summary(roc2)
plot(roc2)
```

I read some previous post suggestiong to use pROC package too, and so I did

```
pred1 <- ifelse ( data$aed == TRUE, 1, 0)
r.lac <- roc(pred1, data$lac)
```

but I kept stopping with an ERROR : "Error: Only strings can be converted to symbols".

Can you give me any suggestion on how to move forward?

Thank you!