R语言中 transform()函数

001、

data <- data.frame(x1 = c(1, 2, 3, 4),            
                   x2 = c(5, 6, 7, 8))                                         ## 测试数据框
data
transform(data, x1 = x1 + 10)                                                  ## 修改列
transform(data, x1 = x1 + 10, x2 = x2 * 10, x3 = x1 + x2, x4 = x1 * x2)        ## 添加列

data <- data.frame(x1 = c(1, 2, 3, 4),
                   x2 = c(5, 6, 7, 8))                            
data
data <- transform(data, x1 = x1 + 10, x2 = x2 * 10, x3 = x1 + x2, x4 = x1 * x2)  
data
data <- transform(data, x2 = NULL, x3 = NULL)      ## 删除列
data