Boosted回归树预测错误

Question

我正在尝试运行一个Boosted回归树，因为我想预测（G）的未来场景，但在我构建模型后，我尝试实际预测我的因变量（G），我得到一个错误。

loyn<-read.csv("FullData.csv", strip.white=T, header=T, sep=',')
library(gbm)
head(loyn)

#G   Site         P        O      T Coral.Cover OCC  PPC
#1  23.023128 Lizard 27.494517 3.702791 25.470         4.2 8.2 20.9
#2  11.547282 Lizard 20.413183 3.664939 25.430         4.2 8.2 20.9

loyn.gbm<-gbm(G~Site+P+O+T+loyn$Coral.Cover+OCC+PPC, data=loyn, distribution="gaussian", train=0.75, interaction.depth=3, shrinkage=0.001, bag.fraction=0.5,cv.folds=3, n.minobsinnode=2, n.trees=10000)

par(mfrow=c(1,2))
(best.iter<-gbm.perf(loyn.gbm, method="cv", overlay=T, oobag.curve=T))
summary(loyn.gbm, n.trees=best.iter)

# here I am asking what value G would have if Site=5, P=20, O=2.7, T=32, #loyn$Coral.Cover=4, OCC=2, PPC=20
new<-predict(loyn.gbm, newdata=data.frame(Site=5, P=20, O=2.7, T=32, loyn$Coral.Cover=4, OCC=2, PPC=20),n.trees=best.iter)

但它一直在说

  

错误：意外＆＃39; =＆＃39; in＆＃34; new＆lt; -predict（loyn.gbm，newdata = data.frame（Site = 5，P = 20，O = 2.7，T = 32，loyn $ Coral.Cover =＆＃34;

我已经检查过，这不是拼写错误。任何帮助将非常感激。谢谢！