如何更改x轴的范围以展开R中的数据点

Question

我试图将两个名为Canopy_index（响应变量）和Lighting（解释变量）的列（下面的数据框）绘制到散点图上。绘制观测值时，数据点主要错误地绘制在图表的左侧（下图），这可能归因于x轴上的错误设置或基本图形设置需要更改。在数据框内，照明列中的值通常介于0到<20之间。

目标

问题在于我想操纵和改变x轴值的范围（在0到20.0之间），以便在第1侧或x轴的整个宽度上以0.5的增量展开观察值。 （即0,0.5,1.0,1.5 ...... 20）。

我尝试了不同的方法，但输出结果总是一样的。此外，情节中有一个虚假的异常值;但是，我无法在数据中检测到这个数据点。

如果有人可以提供帮助，那么非常感谢。

代码

    plot(Canopy_index~Lighting, 
         xaxt="n", pch=16, 
         col="blue", 
         xlab="Artificial Lighting",
         ylab="Canopy Index", 
         data=Distance_light)

 axis(1, at=seq(0, 20, by=0.5), las=2)

剧情

数据

structure(list(Canopy_index = c(75, 85, 75, 35, 85, 95, 85, 65, 
75, 95, 75, 95, 85, 75, 85, 95, 75, 85, 85, 85, 75, 75, 85, 85, 
65, 85, 75, 85, 95, 95, 85, 55, 75, 95, 75, 95, 95, 65, 65, 55, 
95, 85, 85, 45, 85, 85, 35, 95, 85, 85, 35, 85, 45, 85, 85, 85, 
95, 85, 85, 75, 85, 35, 85, 85, 65, 65, 85, 45, 55, 95, 75, 95, 
45, 75, 75, 95, 95, 85, 75, 95, 75, 65, 85, 75, 75, 55, 75, 85, 
85, 85, 15, 75, 85, 85, 85, 95, 85, 85, 85, 75, 85, 85, 95, 65, 
75, 95, 55, 75, 85, 85, 85, 95, 55, 85, 75, 75, 85, 85, 85, 85, 
55, 75, 55, 75, 85, 75, 85, 85, 75, 85, 75, 95, 25, 95, 95, 25, 
75, 75, 85, 35, 55, 85, 65, 85, 75, 85, 85, 85, 75, 65, 85, 85, 
95, 65, 55, 95, 95, 85, 95, 85, 65, 55, 65, 55, 95, 75, 85, 85, 
35, 75, 75, 85, 65, 85, 65, 65, 95, 85, 95, 75, 75, 55, 95, 65, 
85, 65, 15, 35, 55, 95, 15, 15, 75, 65, 85, 5, 5, 35, 35, 85, 
65, 45, 35, 65, 65, 75, 65, 15, 75, 65, 45, 25, 65, 85, 45, 85, 
75, 15, 65, 45, 55, 45, 15, 45, 75, 65, 75, 65, 35, 95, 65, 35, 
35, 65, 45, 75, 35, 75, 85, 35, 55, 65, 85, 65, 65, 85, 55, 15, 
75, 65, 45, 45, 85, 55, 15, 85, 15, 95, 75, 5, 55, 15, 35, 45, 
85, 65, 65, 65, 65, 25, 85, 35, 55, 65, 75, 5, 45, 65, 15, 75, 
55, 65, 55, 35, 75, 65, 65, 85, 35, 65, 55, 75, 15, 55, 65, 75, 
55, 85, 35, 55, 55, 25, 75, 15, 55, 75, 75, 65, 55, 45, 75, 25, 
45, 95, 55, 75, 45, 25, 35, 55, 15, 15, 75, 35, 55, 55, 65, 45, 
65, 25, 55, 45, 65, 65, 25, 25, 65, 45, 95, 55, 25, 55, 85, 45, 
85, 15, 75, 65, 35, 75, 15, 55, 85, 35, 55, 45, 85, 45, 65, 55, 
75, 65, 85), Lighting = c(2.5, 20, 20, 20, 20, 20, 20, 20, 20, 
20, 5, 20, 7.5, 20, 20, 20, 20, 5.5, 15, 20, 5, 20, 20, 20, 20, 
20, 20, 7.5, 20, 20, 7.5, 20, 2.5, 20, 15, 20, 20, 20, 20, 20, 
20, 20, 20, 15, 20, 2.5, 7.5, 15, 20, 20, 20, 20, 7.5, 20, 2.5, 
20, 20, 20, 20, 20, 20, 20, 15, 20, 20, 2.5, 20, 20, 20, 15, 
15, 20, 20, 20, 20, 15, 15, 20, 2.5, 20, 2.5, 20, 20, 20, 20, 
20, 20, 15, 20, 20, 5, 5, 20, 20, 20, 20, 20, 7.5, 20, 20, 20, 
20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 15, 7.5, 
20, 20, 20, 20, 20, 20, 2.5, 20, 20, 2.5, 20, 20, 15, 20, 20, 
20, 7.5, 15, 20, 7.5, 20, 20, 20, 20, 20, 15, 20, 20, 20, 20, 
20, 20, 20, 2.5, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 
15, 7.5, 2.5, 15, 20, 20, 15, 20, 7.5, 8, 20, 20, 20, 20, 20, 
20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 
20, 15, 20, 20, 15, 20, 15, 20, 20, 7.5, 20, 20, 7.5, 20, 20, 
20, 20, 20, 20, 15, 20, 7.5, 20, 20, 20, 20, 20, 20, 20, 20, 
20, 20, 20, 20, 20, 15, 15, 75, 20, 20, 20, 20, 20, 20, 2.5, 
20, 20, 2.5, 15, 20, 20, 7.5, 15, 20, 20, 7.5, 20, 20, 20, 20, 
20, 15, 20, 20, 15, 20, 15, 7.5, 2.5, 20, 7.5, 20, 20, 7.5, 20, 
20, 20, 15, 20, 20, 20, 7.5, 20, 7.5, 20, 20, 20, 7.5, 8, 20, 
20, 20, 20, 20, 20, 20, 20, 7.5, 20, 20, 20, 20, 20, 7.5, 20, 
7.5, 20, 20, 20, 20, 20, 15, 20, 20, 2.5, 20, 20, 20, 20, 20, 
20, 20, 2.5, 7.5, 20, 7.5, 20, 2.5, 20, 20, 20, 15, 20, 20, 20, 
20, 20, 20, 20, 7.5, 20, 20, 20, 20, 20, 20, 20, 20, 20, 2.5, 
7.5, 2.5, 15, 20, 20, 15, 20, 20, 20, 20, 20, 15, 20, 20, 20, 
20, 20, 20, 20, 20, 15)), .Names = c("Canopy_index", "Lighting"
 ), row.names = c(NA, -363L), class = "data.frame")

Answer 1

第230行有一个异常值，这就是你获得该图表的原因。

> Distance_light[Distance_light$Lighting == 75, ]
    Canopy_index Lighting
230           95       75

如果删除它，它可以正常工作：

plot(Distance_light$Lighting[-230], 
     Distance_light$Canopy_index[-230],
     pch=16, 
     col="blue", 
     xlab="Artificial Lighting",
     ylab="Canopy Index",
     xaxt='n')

axis(1, at=seq(0, 20, by=0.5), las=2)