范围相关(?):创建的混合效应模型列表上的 anova()

Scoping-related (?): anova() on list of created mixed-effects models

在我使用 lme 执行混合效果建模的项目中,我尝试比较具有不同相关结构和相等固定部分的模型。由于我将构建很多这样的模型(针对不同的因变量),我尝试编写一个函数来生成具有不同相关结构的模型列表,如下例所示(我真的试图将其保持在最低限度工作示例)。

如果我 运行 一个 anova() 在此列表的元素上,这有效,但 如果 fixedPart 在我的全局环境中。为什么会这样?有没有办法绕过这个问题,让我可以只保留 m 和 re-use/delete fixedPart?

我认为这个问题与 R 中的(词法)范围界定有关,但我找不到真正解决它的方法。

提前致谢!

#Dependencies
library(multilevel)
library(multcomp)

#Generate sample data
nVals = 100
sData = rnorm(nVals, mean = 1, sd = 1)
dF <- data.frame(nSubject = 1:nVals, 
                 v1data = sData + rnorm(nVals, mean = 0, sd = 0.1),
                 v2data = sData + rnorm(nVals, mean = 0, sd = 0.1),
                 v3data = sData + rnorm(nVals, mean = 0, sd = 0.4))
dLongF = reshape(data=dF, varying=c("v1data","v2data","v3data"), v.names='data', direction="long", idvar="nSubject", times=1:3)

#Define function to assess different covariance structures
doAllCorrModels <- function(dataF, subjVarName, visitVarName, fixedPart){
    mList <- vector("list",2)
    mList[[1]] <- lme(fixedPart, #Random intercept, homogeneous variance
             random=as.formula(paste("~1|", subjVarName)),
             data=dataF,
             weights=NULL)
    mList[[2]] <- lme(fixedPart, #Random intercept, heterogeneous variance
             random=as.formula(paste("~1|", subjVarName)),
             data=dataF,
             weights=varIdent(form = as.formula(paste("~1|", visitVarName)))
    )
    mList
}

#Get different covariance structures
dataF <- dLongF
subjVarName <- "nSubject"
visitVarName <- "time"
fixedPart <- data ~ time
m <- doAllCorrModels(dataF, subjVarName, visitVarName, fixedPart)

#This works:
a1 <- anova(m[[1]], m[[2]])

#But this does not:
rm(fixedPart)
a2 <- anova(m[[1]], m[[2]])

您可以使用 do.call:

来避免这种情况
doAllCorrModels <- function(dataF, subjVarName, visitVarName, fixedPart){
  mList <- vector("list",2)
  mList[[1]] <- do.call(lme, list(fixed = fixedPart,
                                  random=as.formula(paste("~1|", subjVarName)),
                                  data=dataF,
                                  weights=NULL))

  mList[[2]] <- do.call(lme, list(fixed = fixedPart,
                                  random=as.formula(paste("~1|", subjVarName)),
                                  data=dataF,
                                  weights=varIdent(form = as.formula(paste("~1|", visitVarName)))))
  mList
}