R plot_ly() sf Choropleth Map, How to set NA or Zero values to a defined colour such as Grey

[krispiepage]

I am trying to find a solution to this solved python issue in R,

How to change colors for NA values to gray in a choropleth map?

[NA%20values%20are%20in%20black] Here above is an ugly choropleth map I created. I’d like to change the na values, those black chunks into light gray so that it’s not that distinct. I only used the built-in color scale. Any way to revise it a bit based on the auto template?

I am using an sf object to create a choropleth map using plotly as such:

plot_ly(postcodeelec, split = ~Postcode, color = ~Standard_E, alpha = 1, showlegend=F)

But some rows have NAs and therefore are outputted as transparent with different colours for the outline of that multipolygon.

Can anyone help?