must a dataset contain all factors in SVM in R - r

Question

I'm trying to find class probabilities of new input vectors with support vector machines in R.
Training the model shows no errors.
fit <-svm(device~.,data=dataframetrain,
kernel="polynomial",probability=TRUE)
But predicting some input vector shows some errors.
predict(fit,dataframetest,probability=prob)
Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) :
contrasts can be applied only to factors with 2 or more levels
dataframetrain looks like:
> str(dataframetrain)
'data.frame': 24577 obs. of 5 variables:
$ device : Factor w/ 3 levels "mob","pc","tab": 1 1 1 1 1 1 1 1 1 1 ...
$ geslacht : Factor w/ 2 levels "M","V": 1 1 1 1 1 1 1 1 1 1 ...
$ leeftijd : num 77 67 67 66 64 64 63 61 61 58 ...
$ invultijd: num 12 12 12 12 12 12 12 12 12 12 ...
$ type : Factor w/ 8 levels "A","B","C","D",..: 5 5 5 5 5 5 5 5 5 5 ...
and dataframetest looks like:
> str(dataframetest)
'data.frame': 8 obs. of 4 variables:
$ geslacht : Factor w/ 1 level "M": 1 1 1 1 1 1 1 1
$ leeftijd : num 20 60 30 25 36 52 145 25
$ invultijd: num 6 12 2 5 6 8 69 7
$ type : Factor w/ 8 levels "A","B","C","D",..: 1 2 3 4 5 6 7 8
I trained the model with 2 factors for 'geslacht' but sometime I have to predict data with only 1 factor of 'geslacht'.
Is it maybe possible that the class probabilites can be predicted with a test set with only 1 factor of 'geslacht'?
I hope someone can help me!!

Answer 1

Add another level (but not data) to geslacht.
x <- factor(c("A", "A"), levels = c("A", "B"))
x
[1] A A
Levels: A B
or
x <- factor(c("A", "A"))
levels(x) <- c("A", "B")
x
[1] A A
Levels: A B