L4作业讲评

1 条形图按频数降序排列

library(tidyverse)
── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
✔ dplyr     1.1.4     ✔ readr     2.1.5
✔ forcats   1.0.0     ✔ stringr   1.5.1
✔ ggplot2   3.5.1     ✔ tibble    3.2.1
✔ lubridate 1.9.3     ✔ tidyr     1.3.1
✔ purrr     1.0.2     
── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
✖ dplyr::filter() masks stats::filter()
✖ dplyr::lag()    masks stats::lag()
ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors
mpg %>% 
  ggplot(aes(fct_infreq(class))) +
  geom_bar(fill = "aquamarine") +
  geom_text(stat = "count", 
            aes(label = after_stat(count)), 
            vjust = -0.5,
            size = 5) +
  labs(title = "Barplot of Class", x = "Class", y = "Count") +
  scale_y_continuous(limits = c(0, 70), 
                     breaks = seq(0, 70, 10)) +
  guides(x = guide_axis(angle = 45)) +
  theme_bw() +
  theme(
     axis.text.x = element_text(size = 12),  # 设置 x 轴刻度字体大小为 12
     axis.text.y = element_text(size = 12),   # 设置 y 轴刻度字体大小为 12
     axis.title = element_text(size = 14),    # 设置坐标轴标题字体大小为 14
     plot.title = element_text(size = 16)     # 设置图表标题字体大小为 16
  )

2 百分比堆栈条形图——展示两个定型变量的分布结构

#  Percentage Stacked Barplot
# 计算每个class中不同drv的比重百分比
mpg_percent <- mpg %>%
                  group_by(class) %>%
                  count(drv) %>%
                  mutate(percent = round(n/sum(n), 2)) %>%
                  ungroup() 
mpg_percent
# A tibble: 12 × 4
   class      drv       n percent
   <chr>      <chr> <int>   <dbl>
 1 2seater    r         5    1   
 2 compact    4        12    0.26
 3 compact    f        35    0.74
 4 midsize    4         3    0.07
 5 midsize    f        38    0.93
 6 minivan    f        11    1   
 7 pickup     4        33    1   
 8 subcompact 4         4    0.11
 9 subcompact f        22    0.63
10 subcompact r         9    0.26
11 suv        4        51    0.82
12 suv        r        11    0.18
ggplot(mpg_percent, 
       aes(class, n, fill = drv)) +
  geom_bar(stat = "identity", 
           position = "fill") +  
  geom_text(aes(label = scales::percent(percent, accuracy = 1), 
                y = percent), 
            position = position_fill(vjust = 0.5), 
            size = 5,
            fontface = "bold",
            color = "white") +
  scale_fill_manual(values = c("cyan4", "darkorchid","deepskyblue"),
                    label = c("Four-wheel",
                              "Front-wheel",
                              "Rear-Wheel"),
                    name = "Drive Type") +
  scale_y_continuous(labels = scales::percent_format(accuracy = 1))+
  labs(title = "Percentage Stacked Barplot by Class and Drive", 
       x = "Class", y = "Percentage") +
  theme(legend.position = "bottom") +
  theme_bw() +
  guides(x = guide_axis(angle = 45)) +
  theme(
     axis.text.x = element_text(size = 12),  # 设置 x 轴刻度字体大小为 12
     axis.text.y = element_text(size = 12),   # 设置 y 轴刻度字体大小为 12
     axis.title = element_text(size = 14),    # 设置坐标轴标题字体大小为 14
     plot.title = element_text(size = 16)     # 设置图表标题字体大小为 16
  )

3 直方图频数标注位置不当

summary(mpg$hwy)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
  12.00   18.00   24.00   23.44   27.00   44.00 
mpg %>% 
  ggplot(aes(hwy))+
  geom_histogram(fill = "darkorchid1",
                 color = "black",
                 binwidth = 2)+
  stat_bin(aes(label = ifelse(after_stat(count) == 0,
                              "",after_stat(count))), 
           binwidth = 2, 
           geom = "text",
           vjust = -0.5)+
  scale_y_continuous(limits = c(0,50), 
                     breaks = seq(0,50,10))+
  scale_x_continuous(breaks = seq(12,44,2))+
  labs(title = "Histogram of Highway Miles per Gallon",
       x = "Highway Miles per Gallon") +
  theme_bw() +
  guides(x = guide_axis(angle = 45)) +
  theme(
     axis.text.x = element_text(size = 12),  # 设置 x 轴刻度字体大小为 12
     axis.text.y = element_text(size = 12),   # 设置 y 轴刻度字体大小为 12
     axis.title = element_text(size = 14),    # 设置坐标轴标题字体大小为 14
     plot.title = element_text(size = 16)     # 设置图表标题字体大小为 16
  )

4 箱线图——按定量变量的中位数降序排列

mpg %>% 
  ggplot(aes(fct_reorder(drv, hwy), hwy, fill = drv)) +
  geom_boxplot() +
  scale_fill_manual(values = c("cyan4", "darkorchid","deepskyblue")) +
  scale_x_discrete(labels = c("Four-wheel",
                            "Front-wheel",
                            "Rear-wheel")) +
  labs(title = "Boxplot of Highway Miles per Gallon by Drive Type", 
       x = "Drive Type", y = "Miles per Gallon") +
  theme_bw() +
  theme(legend.position = "none",
     axis.text.x = element_text(size = 12),  # 设置 x 轴刻度字体大小为 12
     axis.text.y = element_text(size = 12),   # 设置 y 轴刻度字体大小为 12
     axis.title = element_text(size = 14),    # 设置坐标轴标题字体大小为 14
     plot.title = element_text(size = 16)     # 设置图表标题字体大小为 16
  )

5 箱线图——按定量变量的中位数降序排列

library(RColorBrewer)
#查看调色板
display.brewer.all()

mpg %>% 
  ggplot(aes(fct_reorder(class, hwy), hwy, fill = class)) +
  geom_boxplot() +
  scale_fill_brewer(palette = "Paired")+
  labs(title = "Boxplot of Highway Miles per Gallon by Class", 
       x = "Class", y = "Highway Miles per Gallon") +
  theme_bw() +
  guides(x = guide_axis(angle = 45)) +
  theme(legend.position = "none",
     axis.text.x = element_text(size = 12),  # 设置 x 轴刻度字体大小为 12
     axis.text.y = element_text(size = 12),   # 设置 y 轴刻度字体大小为 12
     axis.title = element_text(size = 14),    # 设置坐标轴标题字体大小为 14
     plot.title = element_text(size = 16)     # 设置图表标题字体大小为 16
  )

6 图形比例不适当

mpg %>% 
  ggplot(aes(cty, fill = factor(year), # 设置分组变量，factor(year) 将 year数值变量转换为因子变量
             alpha = 0.5))+
  geom_histogram(binwidth = 2, col = 1)+
  facet_wrap(~ drv,  # 设置切面变量
             labeller = labeller(drv = c("4" = "four-wheel",
                                         "f" = "front-wheel",
                                         "r" = "rear-wheel")), # 设置切面标签
                                 ncol = 1)+
  theme_bw()+
  scale_fill_manual(values = c("cyan", "darkorchid"))+
  labs(title = "Histogram of City Miles per Gallon",
       subtitle = "Grouped by the Type of Drive Engine",
       x = "City Miles per Gallon",
       fill = "Year")

7 与答案完全一致