为什么函数c()接受未记录的参数? [英] Why does function c() accept an undocumented argument?
问题描述
基本函数 c()
的文档将其默认参数显示为
c(...,递归= FALSE)
现在, p>
lst < - list(x = 1:5,y = 6:10)
,然后将列表与
c (lst,recursive = TRUE)
#x1 x2 x3 x4 x5 y1 y2 y3 y4 y5
#1 2 3 4 5 6 7 8 9 10
该列表已折叠,名称已保存。
但我们也可以使用另一个,无证的参数 use.names
,删除名称。 lst,recursive = TRUE,use.names = FALSE)
#[1] 1 2 3 4 5 6 7 8 9 10
为什么 use.names
记录为的其中一个参数 c()
?
我认为这是由于 recursive = TRUE
我相信它必须使用与 unlist
相同的代码。 use.names
参数描述于?unlist
。
The documentation for the base function c()
shows its default arguments as
c(..., recursive = FALSE)
Now, if we define
lst <- list(x = 1:5, y = 6:10)
and then combine the list with
c(lst, recursive = TRUE)
# x1 x2 x3 x4 x5 y1 y2 y3 y4 y5
# 1 2 3 4 5 6 7 8 9 10
the list is collapsed, and the names are kept.
But we can also use another, undocumented argument, use.names
, to remove the names.
c(lst, recursive = TRUE, use.names = FALSE)
# [1] 1 2 3 4 5 6 7 8 9 10
Why isn't use.names
documented as one of the arguments of c()
?
I think that it is due to the recursive=TRUE
which I believe must use the same code as unlist
. The use.names
parameter is described in ?unlist
.
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