R-如何将公式传递给函数内部的with(df，glm(y〜x))构造 [英] R - how to pass formula to a with(df, glm(y ~ x)) construction inside a function

问题描述

我在R中使用mice包对一些丢失的数据进行乘法插补.我需要能够指定一个传递给函数内部with(df, glm(y ~ x))构造的公式.这种with()构造是mice包使用的格式，用于分别在估算数据集的每个中拟合回归模型.

I'm using the mice package in R to multiply-impute some missing data. I need to be able to specify a formula that is passed to a with(df, glm(y ~ x)) construction inside of a function. This with() construction is the format used by the mice package to fit the regression model separately within each of the imputed datasets.

但是，我无法找出导致我无法成功将公式作为参数传递的范围问题.这是一个可重现的示例:

However, I cannot figure out the scoping problems preventing me from successfully passing the formula as an argument. Here is a reproducible example:

library(mice)

data(mtcars)
mtcars[5, 5] <- NA # introduce a missing value to be imputed

mtcars.imp = mice(mtcars, m = 5)

# works correctly outside of function
with(mtcars.imp, glm(mpg ~ cyl))

fit_model_mi = function(formula) {
  with(mtcars.imp, glm(formula))
}

# doesn't work when trying to pass formula into function   
fit_model_mi("mpg ~ cyl")

另请参见此处，尽管没有收到答复，但在R帮助中询问的是同一问题.

Also see here for the same question being asked on R help, although it does not receive an answer.

推荐答案

尝试将公式包装为as.formula

Try wrapping the formula in as.formula

fit_model_mi = function(formula) {
    with(mtcars.imp, glm(as.formula(formula)) )
}

似乎可以正常工作:

> fit_model_mi("mpg ~ cyl")
call :
with.mids(data = mtcars.imp, expr = glm(as.formula(formula)))

call1 :
mice(data = mtcars, m = 5)

nmis :
 mpg  cyl disp   hp drat   wt qsec   vs   am gear carb 
   0    0    0    0    1    0    0    0    0    0    0 

analyses :
[[1]]

Call:  glm(formula = as.formula(formula))

Coefficients:
(Intercept)          cyl  
     37.885       -2.876  

Degrees of Freedom: 31 Total (i.e. Null);  30 Residual
Null Deviance:      1126 
Residual Deviance: 308.3    AIC: 169.3

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