legend - R Plotly stacked bar chart issue -

i using plotly create stacked bar chart below

df <- data.frame(   var1 = c("ny", "ny", "ny", "sfo", "sfo", "sfo"),   var2 =  c("low", "medium", "high", "low", "medium", "high"),   value = c(10,15,20,10,20,25) ) df$var2 <- factor(df$var2, levels = c("low","medium","high"))  # sort factor table df <- arrange(df, var2)  col <- list(   color = ifelse(     df$var2 == "low",     "steelblue",     ifelse(       df$var2 == "medium",       "darkorange",       "olivedrab"     )   ))  # plot plot_ly(   df,   x = ~ var1,   y = ~ value,   color = ~ var2,   marker = col,   type = "bar" ) %>% layout(barmode = "stack") 

there 2 issues facing: first legend not coming correctly (see image).

second since have dynamic table, there possibility there 1 value in var1 , var2

df <- data.frame(var1 = c("ny"),                  var2 =  c("low"),                  value = c(10)) df$var2 <- factor(df$var2, levels = c("low", "medium", "high"))  # sort factor table df <- arrange(df, var2)  col <- list(color = ifelse(   df$var2 == "low",   "steelblue",   ifelse(df$var2 == "medium",          "darkorange",          "olivedrab") ))  # plot plot_ly(   df,   x = ~ var1,   y = ~ value,   color = ~ var2,   marker = col,   type = "bar" ) %>% layout(barmode = "stack") 

in case chart doesn't show up. if have 2 values either in var1 or in var2 chart still shows not one. can tell me how handle this?

thanks, manoj