Question

我（作为R中的初学者）我试图传递一个数据帧列表作为函数的输入，以将一些变量从char更改为日期。当我运行脚本时，它工作。如果我然后在函数中尝试它我没有得到任何错误，但变量的类型仍然是一个字符。您可以在下面找到该功能。提前感谢您的建议。

data <- list(complaints,credit,customers,delivery,subscriptions,formula)

building <- function(x){
for (i in 1:6){
vars <- which(names(x[[i]]) %in% c("StartDate","EndDate","PaymentDate","RenewalDate","ProcessingDate","ComplaintDate","DOB"))

x[[i]][,vars] <- sapply(vars,function(vars) as.Date(x[[i]][,vars],format=f),simplify=FALSE)
}

complaints <- x[[1]]

credit <- x[[2]]

customers <- x[[3]]

delivery <- x[[4]]

subscriptions <- x[[5]]

formula <- x[[6]]
}

building(data)

Answer 1

您正在尝试修改函数中定义的函数中的对象。这在计算机科学中被称为副作用：http://en.wikipedia.org/wiki/Side_effect_%28computer_science%29

你不能在R中这样做。

相反，您可以这样做，例如：

data <- list(complaints,credit,customers,delivery,subscriptions,formula)

building <- function(x){
for (i in 1:6){
vars <- which(names(x[[i]]) %in% c("StartDate","EndDate","PaymentDate","RenewalDate","ProcessingDate","ComplaintDate","DOB"))

x[[i]][,vars] <- sapply(vars,function(vars) as.Date(x[[i]][,vars],format=f),simplify=FALSE)
}

return(x)
}

output <- building(data)

complaints <- output [[1]]

credit <- output [[2]]

customers <- output [[3]]

delivery <- output [[4]]

subscriptions <- output [[5]]

formula <- output [[6]]

列出作为函数的输入

1 个答案: