Question

我有一个空的DF：

CharactersDF <- data.frame(matrix(ncol = 7, nrow = 0))

然后我创建了一个新类：

 RPGcharacter <- function(name, level, rpgClass, race, HP, attack, resist){
   value <- list(name= name, level = level, rpgClass = rpgClass, HP = HP, attack = attack, resist = resist)
   attr(value, "class") <- "RPGcharacter"
   value
 }

然后是新对象：

Artur <- RPGcharacter("Artur", 22, "Warlock", "Dwarf", 130, 12, 3)

如何在空df中将对象添加为一行？我尝试过：

   CharactersDF <- rbind(CharactersDF, Artur)

但是我得到了：

 Warning messages:
1: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  replacement element 1 has 1 row to replace 0 rows
2: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  replacement element 2 has 1 row to replace 0 rows
3: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  replacement element 3 has 1 row to replace 0 rows
4: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  replacement element 4 has 1 row to replace 0 rows
5: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  replacement element 5 has 1 row to replace 0 rows
6: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  replacement element 6 has 1 row to replace 0 rows
7: In `[<-.data.frame`(`*tmp*`, 1, value = list(name = "Artur", level = 22,  :
  provided 6 variables to replace 1 variables

Answer 1

正如Ben在评论中指出的那样，您想使用CharactersDF <- rbind(CharactersDF, Artur)。

您正在CharactersDF和Artur上使用rbind函数，因此您使用rbind()。您正在尝试使用Python风格的语法，其中句点表示您正在调用对象CharactersDF的属性。在这里，您要在两个对象上调用rbind()，然后将结果分配到要存储的任何位置。

Answer 2

尽管rbind解决方案有效，但请注意数据类型和数据结构。空的CharactersDF是包含逻辑类型的数据框

> CharactersDF <- data.frame(matrix(ncol = 7, nrow = 0))
> str(CharactersDF)
'data.frame':   0 obs. of  7 variables:
 $ X1: logi 
 $ X2: logi

Artur是具有数字和字符类型的列表

> Artur <- RPGcharacter("Artur", 22, "Warlock", "Dwarf", 130, 12, 3)
> str(Artur)
List of 6
 $ name    : chr "Artur"
 $ level   : num 22
 $ rpgClass: chr "Warlock"
 $ HP      : num 130
 $ attack  : num 12
 $ resist  : num 3
 - attr(*, "class")= chr "RPGcharacter"

接着rbind，数据类型再次更改为数值和因子。

> CharactersDF <- rbind(CharactersDF, Artur)
> str(CharactersDF)
'data.frame':   1 obs. of  6 variables:
 $ name    : Factor w/ 1 level "Artur": 1
 $ level   : num 22
 $ rpgClass: Factor w/ 1 level "Warlock": 1
 $ HP      : num 130
 $ attack  : num 12
 $ resist  : num 3

确定您需要的类型并与它们一致地工作，或者根据需要故意强迫它们，这样会更安全。

要创建具有预设类型的空数据框，请选中Create an empty data.frame

将对象作为行添加到R中的数据框

2 个答案: