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我需要测试一组参数条件以找到最佳模型（使用drc包）。也就是说，我想将函数参数存储在一个列表中，然后将它们调用到drm()函数中。该drc软件包有一个函数 ( mselect()) 来执行此操作，但已知它会因未知原因而失败 ( https://www.reddit.com/r/Rlanguage/comments/a1bu44/any_idea_what_im_doing_wrong_with_the_mselect/ )。

示例数据

library(drc) # This also loads in the S.alba data
data(S.alba)

head(S.alba)
  Dose  Herbicide DryMatter
1    0 Glyphosate       4.7
2    0 Glyphosate       4.6
3    0 Glyphosate       4.1
4    0 Glyphosate       4.4
5    0 Glyphosate       3.2
6    0 Glyphosate       3.0

尝试失败

# List of function arguments to be assessed e.g. drm(...fct = W1.4(fixed = c(NA, 0.1, NA, NA)
model_list <- list(curve = c(W1.4(fixed = c(NA, 0.1, NA, NA)),
                             LL.4(fixed = c(NA, 0.1, NA, NA))))

# Failed function, attempting to return a list of results
model_select <- function(data, mlist){
    model =  data %>%
        drm(DryMatter ~ Dose, Herbicide, data = . , fct = mlist)
    metric = AIC(model)
    return(metric)
}
model_select(data = S.alba, mlist = model_list)

drm 错误（DryMatter ~ Dose, Herbicide, data = ., fct = mlist）：“fct”列表中的第一个条目不是函数

半工作尝试

model_select_2 <- function(data){
    model =  data %>%
        drm(DryMatter ~ Dose, Herbicide, data = . , fct = W1.4(fixed = c(NA, 0.1, NA, NA)))
    metric = AIC(model)
    return(metric)
}
model_select_2(data = S.alba)

model_select_2(data = S.alba)
[1] 106.9226

期望的输出

model_select(data = S.alba, mlist = model_list)
[1] W1.4-106.9226
[2] LL.4-99.54702
4

1 回答 1

1

部分问题在于您如何创建model_list. 您希望将这些值与list()而不是c(). 后者试图将它们组合成同一个对象。

您可以做的下一件事是sapply遍历曲线列表以获取每个输入的结果。一个工作示例是

model_list <- list(curve = list(W1.4(fixed = c(NA, 0.1, NA, NA)),
                             LL.4(fixed = c(NA, 0.1, NA, NA))))
model_select <- function(data, mlist){
   sapply(mlist$curve, function(curve){
      model <- drm(DryMatter ~ Dose, Herbicide, data = data , fct = curve)
      metric = AIC(model)
   })
}
model_select(data = S.alba, mlist = model_list)
# [1] 106.92259  99.54702
于 2020-02-17T17:21:14.560 回答