将可选参数传递给 r 中的函数

Question

如何将可选参数传递给 R 中的函数？

这方面的一个例子是，我可能希望从模型的特定超参数组合中创建一个函数。但是，我不想配置所有超参数，因为在大多数情况下许多超参数都不相关。

有时，我希望能够手动传入一个我想更改的超参数。我经常在函数中看到 ... ，但无法弄清楚这是否与这种情况有关或至少如何使用它们。

library(gbm)
library(ggplot)
data('diamonds', package = 'ggplot2')

 example_function = function(n.trees = 5){
      model=gbm(formula = price~ ., n.trees = 5, data = diamonds)
}  


# example of me passing in an unplanned argument
example_function(n.trees = 5, shrinkage = 0.02)

这有可能以智能方式处理吗？

Answer 1

您可以使用...参数（记录在 中?dots）从调用函数传递参数。在你的情况下，试试这个：

library(gbm)
library(ggplot2)
data('diamonds', package = 'ggplot2')

example_function <- function(n.trees = 5, ...){
     gbm(formula = price~ ., n.trees = 5, data = diamonds, ...)
}  


# Pass in the additional 'shrinkage' argument 
example_function(n.trees = 5, shrinkage = 0.02)
## Distribution not specified, assuming gaussian 
## gbm(formula = price ~ ., data = diamonds, n.trees = 5, shrinkage = 0.02)
## A gradient boosted model with gaussian loss function.
## 5 iterations were performed.
There were 9 predictors of which 2 had non-zero influence.