CODEWITHSUNDEEP
rlistdataframevectorglm
Michael Pyle
Michael Pyle

Reputation: 65

Passing a vector from a dataframe column, stored in a list, to a glm

I am attempting to fit a Poisson regression model to a dataset in R, whereby I have vectors of different lengths stored in two lists as dataframe columns, as so:

test <- data.frame(a = 1:10, b = rnorm(10))
test$c <- list(length = nrow(test))
test$d <- list(length = nrow(test))

for(i in 1:nrow(test)) {

  test$c[[i]] <- LETTERS[1:sample(10:11, 1)]
  test$d[[i]] <- LETTERS[1:sample(10:11, 1)]
}

I need to build a model to predict a from b and the vectors c and d. As it is not possible to pass lists to a glm, I tried unlisting c and d to feed them into the model, but this just ends up creating one long vector for both c and d, meaning I get this error:

m0.glm <- glm(a ~ b + unlist(c) + unlist(d), data = test)

Error in model.frame.default(formula = a ~ b + unlist(c) + unlist(d),  : 
  variable lengths differ (found for 'unlist(c)')

I feel like there will be a simple solution that I am missing to my problem, but I have not had to attempt to pass a list of vectors to a model before.

Thanks in advance.

Upvotes: 0

Views: 305

Answers (1)

r.user.05apr
r.user.05apr

Reputation: 5456

If the problem is to create a df out of lists, then: 

test <- data.frame(a = 1:10, b = rnorm(10))
test$c <- list(length(nrow(test)))
test$d <- list(length(nrow(test)))

for(i in 1:nrow(test)) {

  test$c[[i]] <- LETTERS[1:sample(10:11, 1)]
  test$d[[i]] <- LETTERS[1:sample(10:11, 1)]
}

# 
do.call(rbind, lapply(test$c, function(x) {
  res <- rep(NA, max(vapply(test$c, length, integer(1))))
  res[1:length(x)] <- x
  res
})) -> test_c_df


do.call(rbind, lapply(test$d, function(x) {
  res <- rep(NA, max(vapply(test$d, length, integer(1))))
  res[1:length(x)] <- x
  res
})) -> test_d_df

test_new <- cbind(test[c("a", "b")], test_c_df, test_d_df)
names(test_new) <- make.unique(names(test_new))

m0.glm <- glm(a ~ ., data = test_new) # data reasonable??

Upvotes: 1

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