eval（expr，envir，enclos）中的错误：object＆＃39; Gender＆＃39;未找到

Question

我从.csv文件中读取数据，并运行以下命令

plsFit <- train(CollegePlans ~ .,data = training,method = "pls",preProc = c("center", "scale"));
toPredict <- c("Female",35800,124,"Not Encouraged","Does not plan to attend")
plsClasses <- predict(plsFit, newdata = toPredict)
并得到以下错误 Error in eval(expr, envir, enclos) : object 'Gender' not found

这是一个结构：

str(training) 
'data.frame':   5401 obs. of  5 variables:
 $ Gender             : Factor w/ 2 levels "Female","Male": 2 1 1 2 1 1 1 1 2 1 ...
 $ ParentIncome       : int  53900 24900 65800 11440 16700 47630 39820 4860 65340 66550 ...
 $ IQ                 : int  118 87 93 117 102 100 127 95 100 112 ...
 $ ParentEncouragement: Factor w/ 2 levels "Encouraged","Not Encouraged": 1 2 2 1 2 1 1 1 1 1 ...
 $ CollegePlans       : Factor w/ 2 levels "Does not plan to attend",..: 2 1 1 2 1 2 2 1 1 2 ...