R语言Plotly绘图图例重复问题求助

你的代码出现图例重复的原因很明确：第一次调用plot_ly()时，已经通过color = ~color参数生成了对应"big"和"small"的两组图例项；后续调用add_trace()又新增了一组轨迹，并且设置showlegend = TRUE，等于把图例又重复渲染了一次。

这里给你两种可行的解决方法：

方法一：关闭新增轨迹的图例显示 #

直接在add_trace()里把showlegend设为FALSE，因为你添加这个trace的目的只是自定义hover提示文本，不需要它生成新图例：

library(plotly)

myFun <- function(n = 5000) {
  a <- do.call(paste0, replicate(5, sample(LETTERS, n, TRUE), FALSE))
  paste0(a, sprintf("%04d", sample(9999, n, TRUE)), sample(LETTERS, n, TRUE))
}

file = data.frame(var1 = rnorm(100,100,100), var2 = rnorm(100,100,100) , var4 = myFun(100))
file$ratio = file$var1/file$var2
file[is.na(file)] <- 0
file$color = ifelse(file$ratio < median(file$ratio), "big", "small")


pal <- c("red", "blue")
pal<- setNames(pal, c("big", "small"))

p = plot_ly(file, x = ~log(var1), y = ~var2, text = ~paste("name:", var4), color = ~color, colors = pal, type = "scatter")

p = p %>% layout(title = 'title1',  xaxis = list(title = 'title2'), yaxis = list(title = 'title3'))

# 修改这里：将showlegend设为FALSE
p =p %>% add_trace( text = paste("name :", file$var4, "<br> var1_val :", file$var1, "<br> var2_val:", file$var2, "<br> Ratio :", file$ratio), hoverinfo = "text", showlegend = FALSE)

方法二：整合hover文本到初始调用（更简洁） #

其实不需要额外调用add_trace()，直接在第一次plot_ly()里定义好hover文本即可，这样从根源避免重复图例：

library(plotly)

myFun <- function(n = 5000) {
  a <- do.call(paste0, replicate(5, sample(LETTERS, n, TRUE), FALSE))
  paste0(a, sprintf("%04d", sample(9999, n, TRUE)), sample(LETTERS, n, TRUE))
}

file = data.frame(var1 = rnorm(100,100,100), var2 = rnorm(100,100,100) , var4 = myFun(100))
file$ratio = file$var1/file$var2
file[is.na(file)] <- 0
file$color = ifelse(file$ratio < median(file$ratio), "big", "small")


pal <- c("red", "blue")
pal<- setNames(pal, c("big", "small"))

# 直接在plot_ly里定义hover文本和hoverinfo，无需后续add_trace
p = plot_ly(file, 
            x = ~log(var1), 
            y = ~var2, 
            text = ~paste("name :", var4, "<br> var1_val :", var1, "<br> var2_val:", var2, "<br> Ratio :", ratio),
            hoverinfo = "text",
            color = ~color, 
            colors = pal, 
            type = "scatter")

p = p %>% layout(title = 'title1',  xaxis = list(title = 'title2'), yaxis = list(title = 'title3'))

两种方法都能解决图例重复的问题，方法二更推荐，因为代码更简洁，逻辑也更清晰。

内容的提问来源于stack exchange，提问作者stats_noob