无法预测 R 中的灾难

Question

I used this formula to get woe with

library("woe")
woe.object <- woe(data, Dependent="target", FALSE, 
                  Independent="shop_id", C_Bin=20, Bad=0, Good=1)

Then I want to predict woe for the test data

test.woe <- predict(woe.object, newdata = test, replace = TRUE)

And it gives me an error

Error in UseMethod("predict") : no applicable method for 'predict' applied to an object of class "data.frame"

Any suggestions please?

Answer 1

For prediction, you cannot do it with the package woe . You need to use the package. Take note of the masking of the function woe , see below:

#let's say we woe and then klaR was loaded
library(klaR)

data = data.frame(target=sample(0:1,100,replace=TRUE),
shop_id = sample(1:3,100,replace=TRUE),
another_var = sample(letters[1:3],100,replace=TRUE))
#make sure both dependent and independent are factors
data$target=factor(data$target)
data$shop_id = factor(data$shop_id)
data$another_var = factor(data$another_var)

You need two or more dependent variables:

woemodel <- klaR::woe(target~ shop_id+another_var, 
data = data)

If you only provide one, you have an error:

woemodel <- klaR::woe(target~ shop_id, 
    data = data)

Error in woe.default(x, grouping, weights = weights, ...) : All factors with unique levels. No woes calculated! In addition: Warning message: In woe.default(x, grouping, weights = weights, ...) : Only one single input variable. Variable name in resulting object$woe is only conserved in formula call.

If you want to predict the dependent variable with only one independent, something like logistic regression will work:

mdl = glm(target ~ shop_id,data=data,family="binomial")
prob = predict(mdl,data,type="response")
predicted_label = ifelse(prob>0.5,levels(data$target)[1],levels(data$target)[0])