如何在R语言中根据另一列值填充Category列的空白值

示例数据代码 #

category <- c("East","BLANK","NorthEast","BLANK","BLANK")
subcat <- c("East","North","SW","NE","SE")
data1 <- as.data.frame(category)
data1$subcat <- subcat

原始数据表格 #

规则与需求 #

• 规则：East类别对应subcat为East、North的行；NorthEast类别对应subcat为SW、NE、SE的行
• 需求：批量将Category列中的BLANK值按上述规则填充，填充后的行用*标注（仅用于展示区分）

批量处理方案 #

方法1：Base R 实现 #

无需额外安装包，直接用基础R语法实现：

# 定义subcat到category的映射规则
cat_mapping <- list(
  East = c("East", "North"),
  NorthEast = c("SW", "NE", "SE")
)

# 生成subcat到category的反向映射表
reverse_map <- unlist(lapply(names(cat_mapping), function(cat) {
  setNames(rep(cat, length(cat_mapping[[cat]])), cat_mapping[[cat]])
}))

# 替换BLANK值
data1$category <- ifelse(data1$category == "BLANK", reverse_map[data1$subcat], data1$category)

方法2：dplyr 实现（可读性更强） #

如果习惯使用tidyverse生态，用dplyr的case_when语法更直观：

library(dplyr)

data1 <- data1 %>%
  mutate(
    category = case_when(
      subcat %in% c("East", "North") ~ "East",
      subcat %in% c("SW", "NE", "SE") ~ "NorthEast",
      TRUE ~ category  # 保留原有非BLANK的Category值
    )
  )

处理后结果 #

内容的提问来源于stack exchange，提问作者chriswang123456