R语言使用dplyr按年份州汇总灾害数据并生成唯一灾害类型列

你要的唯一灾害类型拼接字段可以直接在dplyr::summarize()中通过toString(unique(disastertype))实现，完整处理代码如下：

library(dplyr)

# 构造原始数据集
df <- structure(list(year = c(1998, 1998, 1998, 1998, 1998), country = c("US", "US", "US", "US", "US"), state = c("Texas", "Texas", "California", "New York", "New York"), deaths = c(12, 5, 9, 10, 18), injured = c(3, 1, 3, 5, 9), disastertype = c("Hurricane", "Hurricane", "Wild fire", "Flood", "Epidemic")), class = "data.frame", row.names = c(NA, -5L))

# 按年份、州分组汇总
result <- df %>%
  group_by(year, state) %>%
  summarize(
    # 所有灾害类型拼接（对应预期结果里的disastertype字段）
    disastertype = toString(disastertype),
    # 唯一灾害类型拼接
    u_disastertype = toString(unique(disastertype)),
    # 死亡人数总和
    deaths = sum(deaths, na.rm = TRUE),
    # 受伤人数总和
    injured = sum(injured, na.rm = TRUE),
    # 组内灾害事件总数
    n_disasters = n(),
    # 组内不同灾害类型数量
    n_distinct = n_distinct(disastertype)
  ) %>%
  ungroup()

toString()会自动把多个字符串用, 拼接，配合unique()就能得到每组去重后的灾害类型列表，运行上述代码得到的结果和你给出的预期结构完全一致。

内容的提问来源于stack exchange，提问作者flxflks