r - 线性回归中的错误：对比只能应用于具有 2 个或更多水平的因素

Question

Below is my code:

#Loading Data in R
# Set working directory and read the data. Done by going to sessions: 
#Set working directory
dir()
#Read the data into a data frame
imports<- read.csv("imports-85.csv", as.is = FALSE)
head(imports)

# Preprocessing
#Remove variable
imports$engine_type<-NULL
imports$make<-NULL
imports$num_of_cylinders<-NULL
imports$fuel_type<-NULL
imports<- na.omit(imports)

head(imports)

summary (imports)
str(imports)

# Split the data into training and test set
set.seed(1334)
inde <- sample(2, nrow(imports), replace = TRUE, prob = c(0.7, 0.3))
train.Price<- imports[ind == 1, ]
test.Price <- imports[ind == 2, ]

# 3. Run the method on a training data
myFormula<-Price~.
model<-lm(myFormula, data=train.Price)
print(model)
summary(model)

错误：

model<-lm(myFormula, data=train.Price) contrasts<-( *tmp*, value = contr.funs[1 + isOF[nn]]) 中的错误：对比只能应用于具有 2 个或更多级别的因子

标签： rlinear-regression