R编程中创建点图——dotchart()函数

R语言中的dotchart()函数用于创建指定数据的点图。点图定义为用于绘制克利夫兰点图的图。

Syntax:
dotchart(x, labels = NULL, groups = NULL,
gcolor = par(“fg”),
color = par(“fg”))

Parameters:
x: it is defined as numeric vector or matrix
labels: a vector of labels for each point.
groups: a grouping variable indicating how the elements of x are grouped.
gcolor: color to be used for group labels and values.
color: the color(s) to be used for points and labels.

示例 1：

# Dot chart of a single numeric vector
dotchart(mtcars$mpg, labels = row.names(mtcars),
         cex = 0.9, xlab = "mpg")

输出：

示例 2：

# Plot and color by groups cyl
grps <- as.factor(mtcars$cyl)
my_cols <- c("blue", "darkgreen", "orange")
dotchart(mtcars$mpg, labels = row.names(mtcars),
         groups = grps, gcolor = my_cols,
         color = my_cols[grps],
         cex = 0.9,  pch = 22, xlab = "mpg")

输出：