R语言ggplot2柱状图无显示问题：如何正确设置geom_bar参数？

你遇到的核心问题是两个变量的数值尺度差异过大：annualjobgrowth是几万甚至负几十万的量级，而Rate只是个位数到负十几，直接把它们放在同一个y轴上，柱状条会被压缩成几乎看不见的细线。另外，你没有设置双y轴来适配这两个完全不同量级的变量，这才导致柱状条“消失”了。

下面是修改后的完整代码，以及关键修改点的说明：

修改后的完整代码 #

# Data generation
Month1 <- c(201812,20191,20192,20193,20194,20195,20196, 20197,20198,20199,201910,201911,201912,20201 ,20202,20203,20204,20205,20206,20207 ,20208,20209,202010,202011)
annualjobgrowth<- c(44400,46000,42600,40500,42800,40500,36000, 34000,32300,29900,21900,24500,21000, 23300,16000,-6200,-275600,-249500,-149200, -136500,-129900,-122800,-113900,-109500)
Rate <- c(3.3,3.4,3.1,3.0,3.1,2.9,2.6,2.5,2.3,2.1,1.6,1.7,1.5,1.7,1.1,-0.4, -19.5,-17.6,-10.5,-9.6,-9.1,-8.6,-8.0,-7.7)
cesyoy <- data.frame(Month1,annualjobgrowth, Rate)

# 可选优化：把Month1转成日期格式，让x轴刻度更易读
cesyoy$Month <- as.Date(paste0(substr(cesyoy$Month1, 1, 4), "-", substr(cesyoy$Month1, 5, 6), "-01"), "%Y-%m-%d")

# 绘制双轴图表
library(ggplot2)

# 计算缩放比例：让就业增长的数值范围适配增长率的范围
scale_factor <- max(cesyoy$annualjobgrowth, na.rm = TRUE) / max(cesyoy$Rate, na.rm = TRUE)

firstces <- ggplot(cesyoy) +
  # 核心修改1：对annualjobgrowth做缩放，让它的数值范围和Rate匹配，这样柱状条就能显示
  geom_bar(aes(x = Month, y = annualjobgrowth / scale_factor), stat = "identity", fill = "tan1", colour = "sienna3") +
  # 折线和增长率文本：使用原始Rate值，映射到右侧y轴
  geom_line(aes(x = Month, y = Rate), colour = "blue", size = 1) +
  geom_text(aes(label = Rate, x = Month, y = Rate), colour = "black", vjust = -1) +
  # 就业增长文本：根据数值正负调整位置，避免被柱子挡住
  geom_text(aes(label = annualjobgrowth, x = Month, y = (annualjobgrowth / scale_factor) * ifelse(annualjobgrowth > 0, 0.9, 1.1)), 
            colour = "black", size = 3) +
  # 核心修改2：设置双y轴，把缩放后的数值转换回原始就业增长值
  scale_y_continuous(
    name = "Annual Job Growth",
    breaks = seq(-300000, 50000, 50000),
    labels = seq(-300000, 50000, 50000),
    sec.axis = sec_axis(~ . * scale_factor, name = "Growth Rate (%)")
  ) +
  labs(x = "Month") +
  theme_minimal() +
  theme(axis.text.x = element_text(angle = 45, hjust = 1))

ggsave("firstces.png", width = 12, height = 6)

关键修改说明 #

• 适配尺度差异的双y轴：通过scale_factor把annualjobgrowth缩放至和Rate接近的范围，再用sec_axis把左侧轴的缩放值转换回原始就业增长数值，这样两个系列都能清晰显示。
• 调整geom_bar的y映射：将annualjobgrowth除以scale_factor是让柱状条可见的核心操作，否则它会被Rate的小数值轴压缩成细线。
• 优化文本显示：根据就业增长的正负调整文本位置，确保正数柱子的文本在内部，负数柱子的文本在外部，避免遮挡。
• 日期格式优化：把Month1转成标准日期格式，让x轴的时间刻度更直观易读。

内容的提问来源于stack exchange，提问作者Tim Wilcox