dyShading R dygraph

Question

I am using the dygraphs package and I would like to add multiple shaded regions using the dyShading function. I would like not to have to specify manually the shaded region as it is done in the help of the function:

dygraph(nhtemp, main = "New Haven Temperatures") %>% 
  dyShading(from = "1920-1-1", to = "1930-1-1") %>%
  dyShading(from = "1940-1-1", to = "1950-1-1")

But instead, make a loop on the regions. It would look like something like that (that does not work!):

data %>% dygraph()  %>%
for( period in ok_periods ) dyShading(from = period$from , to = period$to )

Do you have any ideas? Thanks you very much

Answer 1

For example:

#create dygraph
dg <- dygraph(nhtemp, main = "New Haven Temperatures")

#add shades
for( period in ok_periods ) {
  dg <- dyShading(dg, from = period$from , to = period$to )
}

#show graph
dg

If you have periods in a list:

ok_periods <- list(
  list(from = "1920-1-1", to = "1930-1-1"),
  list(from = "1940-1-1", to = "1950-1-1"),
  list(from = "1960-1-1", to = "1970-1-1")
)

Using pipe

If you want to use pipe, you could define a new function

add_shades <- function(x, periods, ...) {
  for( period in periods ) {
    x <- dyShading(x, from = period$from , to = period$to, ... )
  }
  x
}

and use it in a chain:

dygraph(nhtemp, main = "New Haven Temperatures") %>% 
  add_shades(ok_periods, color = "#FFFFCC" )