I have trouble working with formula as with text. What I'm trying to do is to concatenate the formula to the title of the graph. However, when I try to work with the formula as with text, I fail:
model <- lm(celkem ~ rok + mesic)
formula(model)
# celkem ~ rok + mesic
This is fine. Now I want to build string like "my text celkem ~ rok + mesic" - this is where the problem comes:
paste("my text", formula(model))
# [1] "my text ~" "my text celkem" "my text rok + mesic"
paste("my text", as.character(formula(model)))
# [1] "my text ~" "my text celkem" "my text rok + mesic"
paste("my text", toString(formula(model)))
# [1] "my text ~, celkem, rok + mesic"
Now I see there is a sprint function in package gtools, but I think this is such a basic thing that it deserves a solution within the default environment!!
Simplest solution covering everything:
f <- formula(model)
paste(deparse(f, width.cutoff = 500), collapse="")