更新时间:2023-02-10 07:47:03
无需循环( lapply
或其他):
combn(1:4,2)
# [,1] [,2] [,3] [,4] [,5] [,6]
# [1,] 1 1 1 2 2 3
# [2,] 2 3 4 3 4 4
计算组合总和的示例:
combn(1:4,2,FUN=sum)
# [1] 3 4 5 5 6 7
用户定义函数的示例:
x <- 11:14
combn(1:4,2,FUN=function(i,a) sum(a[i]),a=x)
#[1] 23 24 25 25 26 27
这里(在匿名的乐趣中) ction) i
是用作索引和参数的组合 a
是我传递的向量 x
。
Here (in the anonymous function) i
is the combination used as index and argument a
is a vector to which I pass x
.
与用户定义的命名函数相同:
And the same with a user-defined named function:
fun <- function(i,a) sum(a[i])
combn(1:4,2,FUN=fun,a=x)