顏色 R plot 用於二項式變量

Question

I've created a plot with a binomial variable, which has values of 0 and 1. In the resulting plot, I want to clearly see which of the circles in the plot belong to the category 0 and which to 1. I am able to給圓圈不同的顏色，但不要按照我剛才提到的方式。 有人碰巧知道如何完成這項工作嗎？

Answer 1

在基礎 R 中， plot function 采用確定點顏色的參數col 。 考慮以下：

# generate some random data to plot
dataPoints = runif(50)
# plot all points as green points
plot(dataPoints, col = "green", pch = 20)

現在讓我們為每個點創建一個隨機二項式“類型”（0 或 1）：

# generate a random "type" for each point; either 0 or 1
dataType = sample(c(0,1), 50, replace = T)

使用二項式，我們可以制作一個colors的向量，而不是僅僅指定一個顏色：

# create a list of colors for each point, based on "type" of point (0 or 1).  
# 0 = "red" and 1 = "blue".
colorVector = c("red", "blue")[dataType+1]

看看內容...

> dataType
 [1] 1 1 1 0 0 1 0 0 1 0 0 1 0 0 0 0 0 0 0 1 1 0 0 0 1 1 0 1 1 1 0 0 0 1 0 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0
> colorVector
 [1] "blue" "blue" "blue" "red"  "red"  "blue" "red"  "red"  "blue" "red"  "red"  "blue" "red"  "red"  "red"  "red" 
[17] "red"  "red"  "red"  "blue" "blue" "red"  "red"  "red"  "blue" "blue" "red"  "blue" "blue" "blue" "red"  "red" 
[33] "red"  "blue" "red"  "red"  "red"  "red"  "red"  "red"  "blue" "blue" "blue" "blue" "red"  "red"  "blue" "blue"
[49] "blue" "red" 

現在，告訴plot使用 colors 的顏色向量——第一個點將是顏色向量中的第一個顏色，第二個點將是顏色向量中的第二個顏色，等等。

plot(dataPoints, col = colorVector, pch = 20)

最后，如果 colors 的列表比點的列表短，則顏色向量被回收......

plot(1:30, col = c("red", "blue", "green"), pch = 20)