R + Plot.ly + add_trace

Question

I'm trying a second Y axis to my line chart?

plot_ly(C,x =~Ymd,y=~Spots,mode="lines")   # This works.
plot_ly(C,x =~Ymd,y=~ma90,mode="lines")   # This works.
p<- plot_ly(C,x =~Ymd,y=~Spots,mode="lines")%>%   # This doesn't work
add_trace(p,y=~ma90,mode="lines")

Answer 1

You need to specify yaxis = <new yaxis name> in the trace.

library(plotly)
ay <- list(
  tickfont = list(color = "red"),
  overlaying = "y",
  side = "right",
  title = "second y axis"
)
p <- plot_ly() %>%
  add_lines(x = ~1:3, y = ~10*(1:3), name = "slope of 10") %>%
  add_lines(x = ~2:4, y = ~1:3, name = "slope of 1", yaxis = "y2") %>%
  layout(
    title = "Double Y Axis", yaxis2 = ay,
    xaxis = list(title="x")
  )