我们没有您的数据，但让我们创建一个与您自己的数据集相似的数据集，具有相同的名称和近似结构：

set.seed(12)

onlyOne <- data.frame(frequency = 10^rnorm(50, -4), count = 1)
tableOfGraphData <- data.frame(frequency.x = 10^rnorm(50), count.x = 1)

onlyOne <- onlyOne[onlyOne$frequency > 0.0001,]
tableOfGraphData <- tableOfGraphData[which(tableOfGraphData$frequency.x < 1),]

现在我们可以看到，使用您的绘图代码，我们得到了相同的问题：

ggplot() +
  geom_density(data = onlyOne, aes(x = log10(frequency), weight = count), 
               bw = 0.2, fill="black", alpha = 0.5) +
  geom_density(data = tableOfGraphData, 
               aes(x = log10(frequency.x), weight = count.x),
               bw = 0.2, fill = "red", alpha = 0.5) +
  coord_cartesian(xlim = c(-4, 0)) +
  theme_light()

要解决这个问题，只需将coord_cartesian替换为xlim，使用包括密度迹线与x轴相交的点的限制：

ggplot() +
  geom_density(data = onlyOne, aes(x = log10(frequency), weight = count), 
               bw = 0.2, fill="black", alpha = 0.5) +
  geom_density(data = tableOfGraphData, 
               aes(x = log10(frequency.x), weight = count.x),
               bw = 0.2, fill = "red", alpha = 0.5) +
  xlim(-4.6, 0.6) +
  theme_light()