R中两个data.frames之间的条件替换为colname和变量

library(dplyr)

# 读取两个data.frames
df1 <- data.frame(colname = c("A", "B", "C"),
                  variable = c(1, 2, 3))

df2 <- data.frame(colname = c("A", "B", "C"),
                  value = c(10, 20, 30))

# 条件替换
for (i in 1:nrow(df1)) {
  colname <- df1$colname[i]
  variable <- df1$variable[i]
  
  # 在df2中找到匹配的行
  match_row <- df2 %>% filter(colname == colname)
  
  # 替换相应的值
  match_row$value <- variable
  
  # 更新df2中的值
  df2 <- df2 %>% mutate(value = ifelse(colname == colname, variable, value))
}

# 输出结果
print(df2)