CODEWITHSUNDEEP
rplyrlmdplyr
Dieter Menne
Dieter Menne

Reputation: 10215

Predict with a list - revisited

In using predict with a list of lm() objects, @JD Long asked for a solution to a problem which I encounter very often; typically, it comes up when models have been fit and plots are to be produced. JD Long's solution, edited in @Joshua Ulrich's answer was elegant, with the exception of the paste that was required.

@hadley, chief of the ddply empire, published a solution with mdply which I found incomprehensible and far from elegant.

Now the dplyr (and possibly tidyr) is taking over: is there a more intuitive way to handle this common job?

For data and sample code, see JD Long's example cited above.

Upvotes: 2

Views: 202

Answers (1)

Sven Hohenstein
Sven Hohenstein

Reputation: 81693

Using the data in the cited question, you can use the following approach with dplyr.

library(dplyr)
newData %>% 
      group_by(state) %>%
      mutate(pred = predict(modelList[[as.character(state[1])]], 
                            as.data.frame(year)))

However, I am not sure whether this solution is more elegant than the existing ones.

Upvotes: 1

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