R语言遍历DataFrame行实现学生成绩等级自动标注的实现方案

逐行循环（Rowwise Loops） #

原始数据集构造 #

name <- c("John", "Rachel", "Judy", "James", "Oloo")
english <- c("70", "50e", "19c", "38^", "33^")
math <- c("65", "25c", "68", "32^", "50")
science <- c("45", "50", "25c", "27e", "72")
social <- c("56", "76", "42", "23^", "68")    
marks <- data.frame(name, english, math, science, social, stringsAsFactors = FALSE)

等级判定规则 #

• Pass：学生所有成绩无e或^后缀，且全部科目得分≥40
• Supplementary：学生成绩存在^或e后缀；^代表得分低于40，e代表未参加平时考核，即使得分≥40也判定不合格
• Special：学生成绩存在c后缀，但无e或^后缀
• Supplementary & Special：学生成绩同时存在e/^后缀与c后缀
• Discontinued：学生成绩中e、^后缀累计出现次数≥4次

注意：Discontinued判定优先级最高，其余规则按从上到下优先级判定

可运行实现代码 #

基础R实现（无需额外依赖）

# 逐行遍历成绩列，生成comment标注
marks$comment <- apply(marks[, -1], 1, function(row_scores) {
  # 统计e、^后缀出现次数
  cnt_e_caret <- sum(grepl("[e^]", row_scores))
  # 检查是否存在c后缀
  has_c_suffix <- any(grepl("c", row_scores))
  
  # 按优先级判定等级
  if (cnt_e_caret >= 4) {
    return("Discontinued")
  }
  if (cnt_e_caret > 0 && has_c_suffix) {
    return("Supplementary & Special")
  }
  if (cnt_e_caret > 0) {
    return("Supplementary")
  }
  if (has_c_suffix) {
    return("Special")
  }
  # 无特殊后缀时提取纯数字分数，检查是否全部≥40
  pure_scores <- as.numeric(gsub("[^0-9]", "", row_scores))
  if (all(pure_scores >= 40)) {
    return("Pass")
  }
  return(NA_character_)
})

# 输出最终结果
print(marks)

dplyr逐行实现（适合tidyverse用户）

library(dplyr)

marks <- marks %>%
  rowwise() %>%
  mutate(
    cnt_e_caret = sum(grepl("[e^]", c_across(english:social))),
    has_c = any(grepl("c", c_across(english:social))),
    comment = case_when(
      cnt_e_caret >=4 ~ "Discontinued",
      cnt_e_caret >0 & has_c ~ "Supplementary & Special",
      cnt_e_caret >0 ~ "Supplementary",
      has_c ~ "Special",
      all(as.numeric(gsub("[^0-9]", "", c_across(english:social))) >=40) ~ "Pass",
      TRUE ~ NA_character_
    )
  ) %>%
  select(-cnt_e_caret, -has_c) %>%
  ungroup()

print(marks)

输出结果验证 #

运行上述代码后得到的结果与示例完全一致：

name english math science social                 comment
1   John      70   65      45     56                    Pass
2 Rachel     50e  25c      50     76 Supplementary & Special
3   Judy     19c   68     25c     42                 Special
4  James     38^  32^     27e    23^            Discontinued
5   Oloo     33^   50      72     68           Supplementary

内容的提问来源于stack exchange，提问作者John Karuitha