Suppose the dataset, my_data, looks like this

while using offset_a as my offset, the below statement would work:

glm(my_formula, data = my_data, family = 'quasipoisson', offset = offset_a)

However, if I want to write a loop that passes offset_a and offset_b sequentially into glm(), I wouldn't be able to simply pass a character value into the offset argument. Like this:

offset_list <- c("offset_a", "offset_b")

for (k in offset_list){
  ...
  fit = glm(my_formula, data = my_data, family = 'quasipoisson', offset = k)
  ...
}

I tried applying noquote() to the offset, as

fit = glm(my_formula, data = my_data, family = 'quasipoisson', offset = noquote(k))

but it doesn't work either.

Does anyone know how to achieve this?

Furtherly,

if we have a character variable,

statement = "glm(my_formula, data = my_data, family = 'quasipoisson', offset = offset_a)"

Is there any way to pass variable, statement, into glm() directly and get the output successfully?

Much Appreciated!

CodePudding user response：

Probably the easiest way to do this is to put the offset term directly into the formula with reformulate:

resp_var <- "y"
form0 <- "var1   var2   var3*var4"
offset_list <- c("offset_a", "offset_b")
for (k in offset_list){
  ...
  form <- reformulate(response = resp_var,
                      c(form0, sprintf("offset(%s)", k)))
  fit <- glm(form, data = my_data, family = 'quasipoisson')
  ...
}

offset = get(k) would probably also work.

CodePudding user response：

You can use this

offset_list <- c("offset_a", "offset_b")
fit <- list()
for (k in 1:length(offset_list)){
    fit[[k]] = glm(my_formula, data = my_data, family = 'quasipoisson',
    offset = get(offset_list[k]))
}