echarts4r极坐标柱状图tooltip无法显示第三个数据字段z的解决方法

你遇到的问题根源是：默认情况下e_bar(y)仅将x和y字段传入ECharts的系列数据中，z字段未被包含，因此params.data.z会返回undefined。以下是两种可行的解决方法：

方案一：通过customData传递额外字段 #

在e_bar函数中使用customData参数传入z字段，然后在tooltip格式化函数中通过params.customData获取该值：

library(echarts4r)

# 创建示例数据集
df <- data.frame(x = c("A", "B", "C"), y = c(10, 20, 30), z = c("foo", "bar", "baz"))

# 创建极坐标柱状图
df %>%
  e_charts(x) %>%
  # 添加customData参数传入z字段
  e_bar(y, coord_system = "polar", customData = df$z) %>%
  e_angle_axis(startAngle = 90, max = 150, axisLine = list(show = FALSE), axisTick = list(show = FALSE),
               splitLine = list(show = FALSE), axisLabel = list(show = FALSE)) %>%
  e_radius_axis(type = "category", data = df$x, axisLabel = list(interval =0,margin = 50, fontSize= 15, color = 'black'),
                axisLine = list(show = FALSE), axisTick = list(show = FALSE), z = 10) %>% 
  e_polar() %>%
  e_legend(show = FALSE) %>%
  e_tooltip(formatter = htmlwidgets::JS("
    function(params) {
      return params.name + '<br>' + params.value + '<br>' + params.customData;
    }
  "))

方案二：使用aes映射所有字段 #

通过aes同时映射x、y、z三个字段，让ECharts系列数据包含z字段，即可直接通过params.data.z获取值：

library(echarts4r)

# 创建示例数据集
df <- data.frame(x = c("A", "B", "C"), y = c(10, 20, 30), z = c("foo", "bar", "baz"))

# 创建极坐标柱状图
df %>%
  e_charts() %>%
  # 使用aes映射x、y、z三个字段
  e_bar(aes(x = x, y = y, z = z), coord_system = "polar") %>%
  e_angle_axis(startAngle = 90, max = 150, axisLine = list(show = FALSE), axisTick = list(show = FALSE),
               splitLine = list(show = FALSE), axisLabel = list(show = FALSE)) %>%
  e_radius_axis(type = "category", data = df$x, axisLabel = list(interval =0,margin = 50, fontSize= 15, color = 'black'),
                axisLine = list(show = FALSE), axisTick = list(show = FALSE), z = 10) %>% 
  e_polar() %>%
  e_legend(show = FALSE) %>%
  e_tooltip(formatter = htmlwidgets::JS("
    function(params) {
      return params.name + '<br>' + params.value + '<br>' + params.data.z;
    }
  "))

内容的提问来源于stack exchange，提问作者akshay bholee