根据R中的grep列标签结果重新编码多个列

# 导入必要的库
library(dplyr)

# 假设有一个数据框df，包含多个列需要重新编码
df <- data.frame(
  A = c("apple", "banana", "orange"),
  B = c("red", "yellow", "orange"),
  C = c("cat", "dog", "elephant"),
  D = c(1, 2, 3),
  E = c(4, 5, 6)
)

# 使用grep函数查找包含特定模式的列标签的索引
pattern <- "A|B"  # 模式为"A"或"B"
cols <- grep(pattern, colnames(df))

# 使用subset函数选择需要重新编码的列
subset_df <- subset(df, select = cols)

# 使用mutate和ifelse函数重新编码选择的列
recode_df <- mutate(subset_df,
                    A = ifelse(A == "apple", "fruit", "unknown"),
                    B = ifelse(B == "red", "color", "unknown"))

# 输出重新编码后的数据框
recode_df

install.packages("dplyr")