Getting error when applying Smbinning in R - r

Question

I am working on an example from http://r-statistics.co/Logistic-Regression-With-R.html. I have problem with smbinning code. I am trying to get Information Value via using smbinning.
library(smbinning)
# segregate continuous and factor variables
factor_vars <- c ("WORKCLASS", "EDUCATION", "MARITALSTATUS", "OCCUPATION", "RELATIONSHIP", "RACE", "SEX", "NATIVECOUNTRY")
continuous_vars <- c("AGE", "FNLWGT","EDUCATIONNUM", "HOURSPERWEEK", "CAPITALGAIN", "CAPITALLOSS")
iv_df <- data.frame(VARS=c(factor_vars, continuous_vars), IV=numeric(14)) # init for IV results
# compute IV for categoricals
for(factor_var in factor_vars){
smb <- smbinning.factor(trainingData, y="ABOVE50K", x=factor_var) # WOE table
if(class(smb) != "character"){ # heck if some error occured
iv_df[iv_df$VARS == factor_var, "IV"] <- smb$iv
}
}
This is the code given. I cannot understand the reason behind checking class of the smbinning. My general understanding on smbinning is also not that good.
for(vars in factor_vars){
smb <- smbinning.factor(trainingData, y = "ABOVE50K", x = vars )
iv_df[iv_df$VARS == vars, "IV"] <- smb["iv"]
}
When I run this code I am getting some values NA values. So class checking is apparently needed but why?
Thank you very much.

Answer 1

Following the example to the letter, your problem would be the following:
If you do smb <- smbinning.factor(trainingData, y="ABOVE50K", x="EDUCATION") and then smb, you get
1 "Too many categories"
str(trainingData) shows that:
$ EDUCATION : Factor w/ 16 levels...
While the smbinning documentation says that
maxcat - Specifies the maximum number of categories. Default value is 10. Name of x
must not have a dot.
Therefore your solution is to use: smb <- smbinning.factor(trainingData, y="ABOVE50K", x=factor_var, maxcat=16) in the for loop