how to fix emmeans at one specific factor levels

[DominiqueMakowski]

@mattansb I need your help again ☺️

data <- iris
data$Petal.Length_factor <- ifelse(data$Petal.Length < 4.2, "A", "B")
model <- lm(Petal.Length ~ Species * Petal.Length_factor, data = data)

Let's say I want to get the refgrid/means at the "A" level of Petal.Length_factor.

I'd have expected the following to work, yet:

at <- list("Species"=c("setosa", "versicolor", "virginica"), "Petal.Length_factor"=c("A"))
emmeans::ref_grid(model, at = at)

Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) : 
  contrasts can be applied only to factors with 2 or more levels

Any ideas?

[mattansb]

Work for me... 🤷‍♂️

library(emmeans)
data <- iris
data$Petal.Length_factor <- ifelse(data$Petal.Length < 4.2, "A", "B")
model <- lm(Petal.Length ~ Species * Petal.Length_factor, data = data)

at <- list("Species"=c("setosa", "versicolor", "virginica"), "Petal.Length_factor"=c("A"))
emmeans::ref_grid(model, at =  at)
#> 'emmGrid' object with variables:
#>     Species = setosa, versicolor, virginica
#>     Petal.Length_factor = A

^{Created on 2020-05-20 by the reprex package (v0.3.0)}

[DominiqueMakowski]

well...

[DominiqueMakowski]

Works after updating from emmeans_1.4.3.01. Will enforce a higher version then!