在R中对自定义类的元素列表进行排序的列表? [英] Sorting list of list of elements of a custom class in R?
问题描述
我有一个自定义类对象(元组列表).
我也定义了<.myclass >.myclass和==.myclass.
现在我有一个
a <- obj1 # of myclass
b <- obj2 # of myclass
c <- obj3 # of myclass
L <- list(list(a,12,1),list(b,215,23),list(c,21,9))
我想对索引1上的L进行排序，即我有b < c < a，那么我想按list(list(b,215,23),list(c,21,9),list(a,12,1))
我该如何实现?
在搜索中，我发现了如何对特定索引进行排序，并使用它编写了以下函数
magic_sort <- function(lst, sortind, dec = T) {
return(lst[order(sapply(lst,'[[',sortind), decreasing = dec)])
}
但是当我给它赋予索引1时，要对obj1进行排序，它将失败
> magic_sort(L,1)
Error in order(sapply(lst, "[[", sortind), decreasing = dec) :
unimplemented type 'list' in 'orderVector1'
对此有任何解决方法吗?总的来说，基于比较运算符的自定义定义，我是否可以具有排序，最小值等功能?
以下可能会帮助您更好地理解结构: http://pastebin.com/0M7JRLTu
library("sets")
a <- list()
class(a) <- "dfsc"
a[[1]] <- tuple(1L, 2L, "C", "a", "B")
b <- list()
class(b) <- "dfsc"
b[[1]] <- tuple(1L, 2L, "A", "b", "B")
c <- list()
class(c) <- "dfsc"
c[[1]] <- tuple(1L, 2L, "A", "a", "B")
L <- list()
L[[1]] <- list(a, 12, 132)
L[[2]] <- list(b, 21, 21)
L[[3]] <- list(c, 32, 123)
`<.dfsc` <- function(c1, c2) {
return(lt_list(toList(c1),toList(c2)))
}
`==.dfsc` <- function(c1, c2) {
return(toString(c1) == toString(c2))
}
`>.dfsc` <- function(c1, c2) {
return(!((c1 < c2) || (c1 == c2)))
}
lt_list <- function(l1, l2) {
n1 <- length(l1)
n2 <- length(l2)
j = 1
while(j <= n1 && j <= n2) {
if (l1[[j]] != l2[[j]]) {
return (l1[[j]] < l2[[j]])
}
j = j + 1
}
return(n1 < n2)
}
toString.dfsc <- function(x) {
code_string <- ""
#for(ii in x[[1]]) {
for(ii in x) {
code_string <- paste(code_string,"(",ii[[1]],",",ii[[2]],",",ii[[3]],",",ii[[4]],",",ii[[5]],")", sep = "")
}
return(code_string)
}
现在我希望将L设置为list(list(c,_,_),list(b,_,_),list(a,_,_))
来自亚伦的答案确切地说明了什么需要在class ed对象上应用自定义的sort.正如Roland所指出的那样，您实际上实际上需要sort"L"，因此，这就是应该重点关注自定义sort的地方.为了提供灵活性，指定在sort上"L"的元素的哪个索引，一种方法是在"L"上存储一个额外的attr:
将"L"转到适当的对象:
class(L) = "myclass"
attr(L, "sort_ind") = 1L
需要定义
Ops方法(提取数据的相关元素):
"<.myclass" = function(x, y)
{
i = attr(x, "sort_ind") ## also check if 'x' and 'y' have the same 'attr(, "sort_ind")'
x[[1]][[i]] < y[[1]][[i]]
}
"==.myclass" = function(x, y)
{
i = attr(x, "sort_ind")
x[[1]][[i]] == y[[1]][[i]]
}
">.myclass" = function(x, y)
{
i = attr(x, "sort_ind")
x[[1]][[i]] > y[[1]][[i]]
}
和子集方法:
"[.myclass" = function(x, i)
{
y = .subset(x, i)
attributes(y) = attributes(x)
return(y)
}
必须定义上述方法(可能是"<"除外)，因为对sort/order的调用最终将调用rank，而该rank需要.gt以便相应地子集每个元素和比较.
最后，获得酱的获取/设置功能:
sort_ind = function(x) attr(x, "sort_ind")
"sort_ind<-" = function(x, value)
{
attr(x, "sort_ind") = value
return(x)
}
并且:
order(L)
#[1] 3 2 1
sort_ind(L) = 3
order(L)
#[1] 2 3 1
也可以创建sort的方法来包装以上所有内容:
sort.myclass = function(x, sort_ind = attr(x, "sort_ind"), ...)
{
sort_ind(x) = sort_ind
NextMethod()
}
sort(L)
sort(L, sort_ind = 1)
(我假设您的toList函数看起来像toList = function(x) x[[1L]]一样)
I have a custom class object (list of tuples).
I have defined <.myclass >.myclass and ==.myclass on it as well.
Now I have a
a <- obj1 # of myclass
b <- obj2 # of myclass
c <- obj3 # of myclass
L <- list(list(a,12,1),list(b,215,23),list(c,21,9))
I want to sort L, on index 1. i.e. I have b < c < a then, I want sorted L in this form list(list(b,215,23),list(c,21,9),list(a,12,1))
How do I achieve this?
In my searches, I found how to sort on particular index, and using that I wrote the following function
magic_sort <- function(lst, sortind, dec = T) {
return(lst[order(sapply(lst,'[[',sortind), decreasing = dec)])
}
But when I give index 1 to it, to sort on obj1, it fails with
> magic_sort(L,1)
Error in order(sapply(lst, "[[", sortind), decreasing = dec) :
unimplemented type 'list' in 'orderVector1'
Is there any fix for this? In general, can I have functions like sort, minimum and so on, based on custom definition of comparison operators?
Edit: Following perhaps will help understand the structure better: http://pastebin.com/0M7JRLTu
Edit 2:
library("sets")
a <- list()
class(a) <- "dfsc"
a[[1]] <- tuple(1L, 2L, "C", "a", "B")
b <- list()
class(b) <- "dfsc"
b[[1]] <- tuple(1L, 2L, "A", "b", "B")
c <- list()
class(c) <- "dfsc"
c[[1]] <- tuple(1L, 2L, "A", "a", "B")
L <- list()
L[[1]] <- list(a, 12, 132)
L[[2]] <- list(b, 21, 21)
L[[3]] <- list(c, 32, 123)
`<.dfsc` <- function(c1, c2) {
return(lt_list(toList(c1),toList(c2)))
}
`==.dfsc` <- function(c1, c2) {
return(toString(c1) == toString(c2))
}
`>.dfsc` <- function(c1, c2) {
return(!((c1 < c2) || (c1 == c2)))
}
lt_list <- function(l1, l2) {
n1 <- length(l1)
n2 <- length(l2)
j = 1
while(j <= n1 && j <= n2) {
if (l1[[j]] != l2[[j]]) {
return (l1[[j]] < l2[[j]])
}
j = j + 1
}
return(n1 < n2)
}
toString.dfsc <- function(x) {
code_string <- ""
#for(ii in x[[1]]) {
for(ii in x) {
code_string <- paste(code_string,"(",ii[[1]],",",ii[[2]],",",ii[[3]],",",ii[[4]],",",ii[[5]],")", sep = "")
}
return(code_string)
}
Now I want the L desired to be list(list(c,_,_),list(b,_,_),list(a,_,_))
This answer from Aaron demonstrates, exactly, what is needed to apply a customized sort on a classed object. As Roland notes, you -actually- need to sort "L" and, thus, that is where the focus on custom sort should be. To provide flexibility specifying on which index of "L" 's elements to sort, a way would be to store an extra attr on "L":
Turn "L" to an appropriate object:
class(L) = "myclass"
attr(L, "sort_ind") = 1L
Ops methods need to be defined (extract the relevant element of your data):
"<.myclass" = function(x, y)
{
i = attr(x, "sort_ind") ## also check if 'x' and 'y' have the same 'attr(, "sort_ind")'
x[[1]][[i]] < y[[1]][[i]]
}
"==.myclass" = function(x, y)
{
i = attr(x, "sort_ind")
x[[1]][[i]] == y[[1]][[i]]
}
">.myclass" = function(x, y)
{
i = attr(x, "sort_ind")
x[[1]][[i]] > y[[1]][[i]]
}
And a subset method:
"[.myclass" = function(x, i)
{
y = .subset(x, i)
attributes(y) = attributes(x)
return(y)
}
The above methods are necessary (perhaps, except "<") to be defined since a call to sort/order will end up calling rank which needs .gt in order to subset accordingly each element and compare.
Finally, a get/set function for sauce:
sort_ind = function(x) attr(x, "sort_ind")
"sort_ind<-" = function(x, value)
{
attr(x, "sort_ind") = value
return(x)
}
And:
order(L)
#[1] 3 2 1
sort_ind(L) = 3
order(L)
#[1] 2 3 1
A method for sort can be, also, created to wrap all the above:
sort.myclass = function(x, sort_ind = attr(x, "sort_ind"), ...)
{
sort_ind(x) = sort_ind
NextMethod()
}
sort(L)
sort(L, sort_ind = 1)
(I assumed that your toList function would look like something toList = function(x) x[[1L]])
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