simple dplyr + leaflet issue

[ArjunaCap]

given the following:

library('dplyr')
library('leaflet')


df <- data_frame(lat = c(41,40,41,40), lng = c(-70, -70, -69.5, -69.5))

it's unclear why this fails:

df %>% leaflet() %>% addTiles() %>% addPolygons()

error: Don't know how to get path data from object of class tbl_df

the following also fails:

df %>% leaflet() %>% addTiles() %>% addPolygons(lat = lat, lng = lng)

Error in inherits(f, "formula") : object 'lng' not found

and so does:

df %>% leaflet() %>% addTiles() %>% addPolygons(lat, lng)

Error in inherits(f, "formula") : object 'lat' not found

this works:

df %>% leaflet() %>% addTiles() %>% addPolygons(lat = df$lat, lng = df$lng)

Am I missing something fundamental?

but of course having to re-specify "df" in the addPolygons call seems to defeat the convenience of piping

[Dennis Murphy]

Hi:

The Details section of the help page for leaflet::leaflet() provides a
clue: use ~ before the variable names. Applying this to your problem,

df %>% leaflet() %>% addTiles() %>% addPolygons(lat = ~lat, lng = ~lng)

produces a bow-tie shaped object in my web browser. Is that what you expected?

Dennis

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[Michael Cawthon]

Ah. This detail I'd forgotten. Thank you. 

Strangely enough, addCircleMarkers() in the pipe works- it's unclear why addPolygons() would be different in how explicitly lat/lng would need to be specified. 

-- 

Michael Cawthon
Chief Investment Officer
Green Street Energy LLC
mcaw...@greenstenergy.com
p: 479-442-1407