r - R-tryCatch警告消息正在写入数据

Question

我正在尝试实现

我正在尝试使用tryCatch语句在R中编写自己的“插补”函数:
1.输出包含功能名称的警告/错误消息，这样我可以更轻松地进行调试。
2.如果函数运行正常，但未估算所有缺失值，则发出警告。

ImputeVariables <- function(impute.var, impute.values, 
                        filter.var){
# function to impute values. 
# impute.var = variables with NAs
# impute.values = the missing value(s) to replace NAs, value labesl are levels
# filter.var = the variables to filter on. 
# filter.levels = the categories of filter.var
tryCatch({
    filter.levels <- names(impute.values)
    # Validation
    stopifnot(class(impute.var) == class(impute.values), 
             length(impute.values) > 0,
             sum(is.na(impute.values)) == 0)
    # Impute values
    for(level in filter.levels){
        impute.var[which(filter.var == level & is.na(impute.var))] <- 
            impute.values[level]
    }
    # Check if all NAs removed.  Throw warning if not. 
    if(sum(is.na(impute.var)) > 0){
        warning("Not all NAs removed")
    }
    # Return values
    return(impute.var)

}, 
    error = function(err) print(paste0("ImputeValues: ",err)),
    warning = function(war) print(paste0("ImputeValues: ",war))
)
}

impute.var和 filter.var是从data.frame中获取的 vector (它们是Ages和Titles的 vector (例如'Mr'，'Mrs') impute.values是与 impute.var相同类型的 vector ，但带有从 filter.var提取的标签(即 c('Mr' = 30, 'Mrs' = 25...)的形式)

问题

为了检查我的验证是否正常工作，我向该函数提供了NA的命名 vector ，因此:

ages <-   c(34, 22, NA, 17, 38, NA)
titles <- c("Mr", "Mr", "Mr", "Mrs", "Mrs", "Mrs")
ages.values <- c("Mr" = NA, "Mrs" = NA)

ages.new <- ImputeVariables(ages, ages.values, titles)

print(ages.new)

但是它输出以下内容:

 "ImputeValues: Error: class(impute.var) == class(impute.values) is not TRUE\n"
 "ImputeValues: Error: class(impute.var) == class(impute.values) is not TRUE\n"

这两行是由于函数打印了 ages.new vector ，并且以下打印语句打印了 ages.new(为什么？)

如果我注释掉验证( stopifnot函数)，那么我会得到:

"ImputeValues: simpleWarning in doTryCatch(return(expr), name, parentenv, handler): Not all NAs removed\n" 

我在问什么

为什么tryCatch块的行为如此？

我的验证和错误处理策略是否最佳(显然没有错误)？

非常感谢您的宝贵时间。

抢

Answer 1

谢谢奥利弗。

现在的工作代码是:

 ImputeVariables <- function(impute.var, impute.values, 
                        filter.var){
# function to impute values. 
# impute.var = variables with NAs
# impute.values = the missing value(s) to replace NAs, value labesl are levels
# filter.var = the variables to filter on. 
# filter.levels = the categories of filter.var
tryCatch({
    filter.levels <- names(impute.values)
    # Validation
    stopifnot(class(impute.var) == class(impute.values), 
             length(impute.values) > 0,
             sum(is.na(impute.values)) == 0)
    # Impute values
    for(level in filter.levels){
        impute.var[which(filter.var == level & is.na(impute.var))] <- 
            impute.values[level]
    }
    # Check if all NAs removed.  Throw warning if not. 
    if(sum(is.na(impute.var)) > 0){
        warning("Not all NAs removed")
    }
    # Return values
    return(impute.var)

}, 
    error = function(err) stop(paste0("ImputeValues: ",err)),
    warning = function(war) {
        message(paste0("ImputeValues: ",war))
        return(impute.var)}
)
}