如何按姓名与分组筛选DataFrame中温度列的最大绝对值数据？

原始数据构造 #

Name <- c("Jon", "Jon", "Maria", "Maria","dan","dan","Jon", "Jon", "Maria", "Maria","dan","dan")
tem <- c(-23, -41, 32, 58,30,10,-20,63,-30,-33,55,66)
group <- c("max", "min", "max", "min","max","min","max", "min", "max", "min","max","min")
var <- c("lan", "lan", "lan", "lan","lan","lan","sea", "sea", "sea", "sea","sea","sea")
df <- data.frame(Name, tem,group,var)

解决方法（使用dplyr包） #

先确保已安装并加载dplyr包，然后通过分组筛选实现需求：

# 安装dplyr（首次使用时执行）
# install.packages("dplyr")
library(dplyr)

# 分组筛选绝对值最大的记录
result <- df %>%
  group_by(Name, group) %>%
  filter(abs(tem) == max(abs(tem))) %>%
  ungroup()

# 输出结果（隐藏行号）
print(result, row.names = FALSE)

代码说明 #

• group_by(Name, group)：按Name和group两个字段对数据分组
• filter(abs(tem) == max(abs(tem)))：在每个分组内，筛选出tem列绝对值等于该组最大绝对值的行
• ungroup()：取消分组结构，将结果转换为普通数据框

运行结果 #

Name tem group var
   Jon -23   max lan
 Maria  32   max lan
 Maria  58   min lan
   Jon  63   min sea
   dan  55   max sea
   dan  66   min sea

内容的提问来源于stack exchange，提问作者bic ton