Error in table(data, reference, dnn = dnn, ...) : all arguments must have the same length error while making confusion matrix.

[jalaj_geete]

insure=read.csv(choose.files(),header = TRUE)
insure
View(insure)
dg=ggplot(data=insure,aes(x=age,y=charges,color=region))+geom_point()+geom_smooth()
dg
set.seed(12345)

insure2=subset(insure,select = -c(region))
View(insure2)

partss=createDataPartition(insure2$smoker,p=0.75,list=F)
partss

train7=insure2[partss,]
train7
test7=insure2[-partss,]
test7

na.omit(insure2)
is.na(insure2)
dim(train7)
table(insure2)
dim(test7)


modelfit7=train(as.factor(smoker)~.,data=train7,method="glm")
modelfit7
prediction7=predict(modelfit7,data=test7)
prediction7

prediction7b=confusionMatrix(prediction7,as.factor(test7$smoker))
prediction7b

[technocrat]

Hi, and welcome!

I'm sure that you have heard of lazy evaluation in R. The same principle applies in the community here, which is why a reproducible example, called a reprex is important. The question will attract more and better answers.

[jalaj_geete]

Hi, Thanks for the reply

I am a beginner and dont know much about R. I am getting the mentioned error. Any visible mistake that i did in the coding??

[technocrat]

There may be, but it's too difficult to peer at what we're working with, which is why a reprex is so helpful.

[andresrcs]

@jalaj_geete

prediction7b=confusionMatrix(prediction7,as.factor(test7$smoker))

The error message comes from this line of code, apparently prediction7 and test7 don't have the same number of rows, possibly because there are NAs in test 7 but we can't be sure with out a proper REPRoducible EXample (reprex).