course_demo_ggplot

library(tidyverse)

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✔ ggplot2   3.5.2     ✔ tibble    3.2.1
✔ lubridate 1.9.4     ✔ tidyr     1.3.1
✔ purrr     1.0.4     
── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
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sample_data |> glimpse() 

Rows: 1,000
Columns: 4
$ job       <chr> "Salesperson", "Office Worker", "Engineer", "Office Worker",…
$ age       <dbl> 28, 25, 36, 34, 28, 29, 38, 30, 34, 35, 33, 26, 31, 34, 26, …
$ education <fct> Bachelor's Degree, Bachelor's Degree, Bachelor's Degree, Bac…
$ income    <dbl> 77971.7, 43284.3, 81532.6, 52892.4, 50579.5, 56568.3, 44288.…

Note

在ggplot2中，绘图就像搭建一座房子：首先用ggplot(data, aes())打好地基 ——data是建筑材料（数据集），aes()则是设计图纸，把数据变量 “装修” 成图上的元素（比如用age变量做横轴，income做纵轴，education决定颜色分组），再加上各种geom。

单变量：分类

柱状图

ggplot(data = sample_data,
       mapping = aes(x = education)
) + 
  geom_bar()

单变量：数值

直方图

ggplot(data = sample_data,
       mapping = aes(x = age)
) +
  geom_histogram()

`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

密度图

ggplot(data = sample_data,
       mapping = aes(x = age)
) +
  geom_density()

箱线图

ggplot(data = sample_data,
       mapping = aes(x = age)
) +
  geom_boxplot()

双变量：数值 + 数值

散点图

ggplot(data = sample_data,
       mapping = aes(x = age, y = income)
) +
  geom_point()

折线图

ggplot(data = sample_data,
       mapping = aes(x = age, y = income)
) +
  geom_line()

拟合曲线图

ggplot(data = sample_data,
       mapping = aes(x = age, y = income)
) +
  geom_smooth()

`geom_smooth()` using method = 'gam' and formula = 'y ~ s(x, bs = "cs")'

双变量：分类 + 数值

箱线图

ggplot(data = sample_data,
       mapping = aes(x = education, y = income)
) +
  geom_boxplot()

小提琴图

ggplot(data = sample_data,
       mapping = aes(x = education, y = income)
) +
  geom_violin()

基础上使用”fill”/“color”增加分类变量

双变量：分类 + 分类

柱状图 + “fill”

ggplot(data = sample_data,
       mapping = aes(x = education, fill = job)
) + 
  geom_bar()

三变量：数值 + 数值 + 分类

散点图 + “color”

ggplot(data = sample_data,
       mapping = aes(x = age, y = income, color = education)
) + 
  geom_point()

拟合曲线图 + “color”

ggplot(data = sample_data,
       mapping = aes(x = age, y = income, color = education)
) + 
  geom_smooth()

`geom_smooth()` using method = 'loess' and formula = 'y ~ x'

双变量：数值 + 分类

密度图 + “color”

ggplot(data = sample_data,
       mapping = aes(x = age, color = job)
) +
  geom_density()

密度图 + “fill”

ggplot(data = sample_data,
       mapping = aes(x = age, fill = job)
) +
  geom_density(alpha = 0.5) # 不透明度0.5