如何对另一个子集进行子集化或“分组”？

Question

我正在尝试对数据集（巴西的凶杀率）进行一些分析。数据很简单，但我正在学习，所以对我来说不是那么简单......在按年份、州和地区创建分组信息的子集之后，我仍然无法理解如何将这些子集分组为更大的子集（按地区划分的州） .我想将所有区域分组到一个更大的“子集”上，这样我就可以绘制信息，而不是让数据按状态显示，而是按区域显示。这可能既简单又愚蠢，但我浪费了几个小时谷歌搜索和尝试不同的代码，到目前为止没有任何效果。

North <- subset(Homicides, State == 'AM' | State == 'RR'| State == 'AP' | State == 'PA' | State == 'TO' | State == 'RO' | State == 'AC')
Northeast <- subset(Homicides, State == 'MA' | State == 'PI'| State == 'CE' | State == 'RN' | State == 'PE' | State == 'PB' | State == 'SE' | State == 'AL' | State == 'BA')
Midwest <- subset(Homicides, State == 'MT' | State == 'MS'| State == 'GO'| State == 'DF')
Southeast <- subset(Homicides, State == 'SP' | State == 'RJ'| State == 'ES'| State == 'MG')
South <- subset(Homicides, State == 'PR' | State == 'RS'| State == 'SC')
AllRegions <- # How to group them so I can plot correctly?

对于情节代码：

ggplot(Homicides, aes(x = Year, y = TotalRate, group = State, color = State)) + # Where state should be the regions instead
  geom_line() +
  geom_point(size = 1) + 
  ggtitle("Total Homicides") +
  theme_hc() +
  scale_colour_hc()

数据集文件的样子（便于理解）

    State Year TotalRate FirearmsRate
1      AC 1979        34           13
2      AC 1980        26           12
3      AC 1981        28            8
4      AC 1982        41           18
5      AC 1983        33           12
6      AC 1984        36           13

Answer 1

正如@Giovanni 所说，按地区汇总数据是这里的关键。这是我认为使用dplyr 包解决的典型问题，它是tidyverse 的一部分

您提供的示例数据没有回答问题所需的所有组成部分，因此我将其更改为包含多个州，并且每个州的年份都相同：

df <- read.table(header = TRUE, text ="
State Year TotalRate FirearmsRate
AC    1979        34           13
AM    1980        26           12
MA    1979        28            8
PI    1980        41           18
MT    1979        33           12
MS    1980        36           13")

然后我将您的标准应用于新列：

df_summary <- df %>%
 mutate(region = case_when(
         State == 'AM' | State == "AC" ~ "North",
         State == "MA" | State == "PI" ~ "Northeast",
         State == "MT" | State == "MS" ~ "Midwest")) %>%
 group_by(region, Year) %>%
 summarize(average_rate = mean(TotalRate))

# which looks like this

# A tibble: 6 x 3
# Groups:   region [3]
  region     Year average_rate
  <chr>     <int>        <dbl>
1 Midwest    1979           33
2 Midwest    1980           36
3 North      1979           34
4 North      1980           26
5 Northeast  1979           28
6 Northeast  1980           41

然后你可以在你的ggplot 中使用它（我没有使用你的主题元素，因为我不确定它们来自哪里：

ggplot(df_summary, aes(x = Year, y = average_rate, color = region)) +
  geom_line() +
  geom_point(size = 1) + 
  ggtitle("Total Homicides")