R - 随机森林未正确加载

Question

我在加载随机森林模型并将其应用到带有 raster::predict 的栅格时遇到问题.

通常，当我在 R session 中创建随机森林模型时，输入其名称并按 Enter 键，我会收到以下打印输出:

> rf_model
Call:
 randomForest(formula = AGB_mean ~ B1_med + B2_med + B4_med +      B5_med + B6_med + B7_med + B1_sd + B2_sd + B4_sd + B5_sd +      B6_sd + B7_sd + NDVI + EVI + EVI2, data = all.training, importance = TRUE, na.action = na.roughfix) 
               Type of random forest: regression
                     Number of trees: 500
No. of variables tried at each split: 5

          Mean of squared residuals: 4866.287
                    % Var explained: 52.48

当我使用 predict 将此 session 中模型应用于栅格时，我可以做出成功的预测。

当我使用 readRDS 加载保存的随机森林模型并输入模型名称时，如下所示:

> rf_model <- readRDS('model.rds')
> rf_model

我收到了 rf_model 中所有信息的完整打印件(即 rf_model$call, rf_model$type... rf_model$terms)，当我尝试进行预测时，我收到以下错误:

Error in UseMethod("predict") : 
  no applicable method for 'predict' applied to an object of class "c('randomForest.formula', 'randomForest')"

在正确加载随机森林对象时，我在这里遗漏了什么吗？

Answer 1

例如:

library(randomForest)
rf_model <- randomForest(Species ~ .,data=iris)
saveRDS(rf_model,'model.rds')
quit()

如果我再次启动 R，我需要加载库:

rf_model <- readRDS('model.rds')
predict(rf_model)
Error in UseMethod("predict") : 
  no applicable method for 'predict' applied to an object of class "c('randomForest.formula', 'randomForest')"

library(randomForest)
head(predict(rf_model))

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