在 R 编程中的核密度图的两点之间添加颜色 - 使用 with()函数

plot()和with()函数用于在 R 语言中的核密度图的两个点的特定区域之间绘制和添加颜色。

绘制核密度图

R语言中的plot()函数用于绘制核密度图

Syntax: plot(dens_x)

Parameters:
dens_x: Default plot of density.

Returns: Kernel density plot

# Create example data
  
set.seed(72500)  
x <- rnorm(800)
dens_x <- density(x)
plot(dens_x)       

输出：

为绘图添加颜色

with()函数用于在图形的两点之间添加颜色。

Syntax:
with(dens_x,
polygon(x = c(x),
y = c(0, y[x_low:x_high], 0),
col = ” “))

Parameters:
dens_x: Default plot of density.
x_low, x_high: lower limit and upper limit of colored area
col: Name of color

Returns: Color plot between to particular plots with specified color.

# color the plot
  
set.seed(72500)  
x <- rnorm(800)
dens_x <- density(x)
plot(dens_x)       
x_low <- min(which(dens_x$x >= - 0.5))   # Define lower limit of colored area
x_high <- max(which(dens_x$x < 1))       # Define upper limit of colored area
with(dens_x,                             # Add color between two limits
     polygon(x = c(x[c(x_low, x_low:x_high, x_high)]),
             y = c(0, y[x_low:x_high], 0),
             col = "darkgreen"))

输出：