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Accepted
LucaS
Asked: 2024-08-22 08:17:03 +0800 CST

将数据框从函数放入工作区

  • 772

我有一个相当简单的函数，其中包含一个 for 循环，将特定编码的缺失值转换为 NA：

make_na <- function(value, df){
  for(thisvar in names(df)){
    df[[thisvar]][df[[thisvar]] == value] <- NA
    num_NA <- length(df[[thisvar]][is.na(df[[thisvar]])])
    print(paste0(thisvar, " has ", num_NA, " NA's"))
  }  
  return(df)
}

运行该函数可以正确打印修改后的数据框，但我不知道如何将数据框放回工作区。我也尝试new_dat <- return(df)将数据框分配给一个对象，但那也不起作用。显然我遗漏了一些简单的东西。

2 个回答

  1. Best Answer

    我认为您可以尝试 df = make_na(value, df)。以下是一个例子。

    Names <- c("Jane", "Sam", "Jose", "Amy") 
Ages <- c(42, 33, 39, 25) 
Locations <- factor(c("West", "West", "South", "South"))

EmpData <- data.frame(Name=Names, Age=Ages, Location=Locations)

print(EmpData)

make_na <- function(value, df){
  for(thisvar in names(df)){
    df[[thisvar]][df[[thisvar]] == value] <- NA
    num_NA <- length(df[[thisvar]][is.na(df[[thisvar]])])
    print(paste0(thisvar, " has ", num_NA, " NA's"))
  }  
  return(df)
} 

df = make_na(33, EmpData)

print(df)

    这样，您就可以获得带有 NA 的数据框

    • 0

  2. 我认为我们不需要明确的循环；尝试：

     X = data.frame(Name=c("Jane", "Sam", "Jose", "Amy"), Age=c(42, 33, 39, 25), 
                Location=c("West", "West", "South", "South"))
 
 insertNA = \(d0, x) {
   stopifnot(is.data.frame(d0))
   d0[d0 == x] = NA
   n = colSums(is.na(d0)); cn = colnames(d0)
   writeLines(paste(cn, "has", n, "NA's."), sep = "\n")
   cat("---------------------\n")
   d0
 }
 
 X = insertNA(X, 33)
#> Name has 0 NA's.
#> Age has 1 NA's.
#> Location has 0 NA's.
#> ---------------------
 X
#>   Name Age Location
#> 1 Jane  42     West
#> 2  Sam  NA     West
#> 3 Jose  39    South
#> 4  Amy  25    South

    用覆盖X（在您的情况下df）X = insertNA(X, 33)。

    • 0

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