J48决策树无法处理字符串属性

Question

下面给出了我使用的代码，并且还显示了错误 数据位于https://data.gov.in/catalog/historical-daily-ambient-air-quality-data，仅下载2015年的德里数据 click here for sample dataset and to know about it

//Importing the data

> library(readxl)

> aq_delhi_2015 <- read_excel("C:/Users/NAMIT/Desktop/aq_delhi-2015.xlsx")

//View the data

> View(aq_delhi_2015)

//Subsetting the data for the station code=55

> delhi1 <- subset(aq_delhi_2015,aq_delhi_2015$`Stn Code`=="55")

//view the dataset Delhi1

> View(delhi1)

//Importing the necessary packages

> library("RWeka", lib.loc="~/R/win-library/3.5")
> library("party", lib.loc="~/R/win-library/3.5")

//Creating the decision tree

> tree1 <- J48(delhi1$`Stn Code`~.,data = delhi1)

  

//错误   .jcall（o，“ Ljava / lang / Class;”，“ getClass”）中的错误：weka.core.UnsupportedAttributeTypeException：weka.classifiers.trees.J48：无法处理字符串属性！