| Type: | Package |
| Title: | Combinatorics Iterators |
| Version: | 1.0.3 |
| Description: | Provides iterators for combinations, permutations, subsets, and Cartesian product, which allow one to go through all elements without creating a huge set of all possible values. |
| License: | MIT + file LICENSE |
| Depends: | R (≥ 3.1) |
| LazyData: | TRUE |
| LinkingTo: | Rcpp |
| Imports: | iterators, itertools, Rcpp |
| RoxygenNote: | 6.0.1 |
| Suggests: | combinat, foreach, testthat |
| URL: | https://github.com/kota7/combiter |
| BugReports: | https://github.com/kota7/combiter/issues |
| NeedsCompilation: | yes |
| Packaged: | 2017-12-04 10:48:57 UTC; kota |
| Author: | Kota Mori [aut, cre] |
| Maintainer: | Kota Mori <kmori05@gmail.com> |
| Repository: | CRAN |
| Date/Publication: | 2017-12-04 12:36:31 UTC |
First Value of Iterator
Description
getFirst is a generic function that returns the
first value of iterators
Usage
getFirst(obj, ...)
Arguments
obj |
an R object |
... |
additional arguments |
Value
iterator value, format dependes on the objects
Last Value of Iterator
Description
getFirst is a generic function that returns the
last value of iterators
Usage
getLast(obj, ...)
Arguments
obj |
an R object |
... |
additional arguments |
Value
iterator value, format dependes on the objects
Does This Iterator Have A Previous Element
Description
hasPrev is a generic function that indicates if the
iterator has another element backward.
Usage
hasPrev(obj, ...)
Arguments
obj |
an R object |
... |
additional arguments |
Value
Logical value indicating whether the iterator has a previous element.
Cartesian Product Iterator
Description
Create an iterator going through Cartesian product of several items.
Usage
icartes(nvec)
icartesv(...)
Arguments
nvec |
integer vector of number of items |
... |
set of iterables (subsettable by |
Details
icartesiterates through all combinations of integersicartesviterates through all combinations of general values
Value
iterator object
Examples
x <- icartes(c(3, 2, 4))
ct <- 0
while (hasNext(x))
{
ct <- ct + 1
i <- nextElem(x)
cat(sprintf("%3d : %s\n", ct, paste0(i, collapse = " ")))
}
x <- icartesv(Month=c("Jan", "Feb", "Mar"),
Loc=c("NY", "LA"),
By=c("car", "plane", "bus"))
as.list(x)
Combination Iterator
Description
Create an iterator for all combinations k integers out of 1 through n.
Usage
icomb(n, k)
icombv(values, k)
Arguments
n |
positive integer |
k |
positive integer no greater than n |
values |
iterable (subsettable by |
Details
icombiterates through integer vectorsicombviterates through general values
Value
iterator object
Examples
x <- icomb(5, 3)
ct <- 0
while (hasNext(x))
{
ct <- ct + 1
i <- nextElem(x)
cat(sprintf("%3d : %s\n", ct, paste0(i, collapse = " ")))
}
as.list(icombv(c("A", "G", "C"), 2))
Permutation Iterator
Description
Create an iterator for all permutations of size k of integers 1 to n.
Usage
iperm(n, k = n)
ipermv(values, k = length(values))
Arguments
n |
positive integer |
k |
positive integer |
values |
iterable (subsettable by |
Details
ipermiterates through integer vectorsipermviterates through general values
Value
iterator object
Examples
x <- iperm(3)
ct <- 0
while (hasNext(x))
{
ct <- ct + 1
i <- nextElem(x)
cat(sprintf("%3d : %s\n", ct, paste0(i, collapse = " ")))
}
as.list(ipermv(c("R", "G", "B")))
Subset Iterator
Description
Create an iterator for all subsets of integers 1 through n.
Usage
isubset(n)
isubsetv(values)
Arguments
n |
positive integer |
values |
iterable (subsettable by |
Details
isubsetiterates through integer vectorsisubsetviterates through general values
Value
iterator object
Examples
x <- isubset(3)
ct <- 0
while (hasNext(x))
{
ct <- ct + 1
i <- nextElem(x)
cat(sprintf("%3d : %s\n", ct, paste0(i, collapse = " ")))
}
as.list(isubsetv(letters[1:4]))
Get Previous Element of Iterator
Description
prevElem is a generic funcion to move an
iterator object one step backward.
Usage
prevElem(obj, ...)
Arguments
obj |
an R object |
... |
additional arguments |
Value
iterator value
Factory of Iterators defined by Recursive Transition Functions
Description
This is a constructor for custom iterator objects. It requires four functions, "next", "prev", "first", and "last", and additional parameters.
The state of the constructor is characterized by the variable i.
The "next" and "prev" function must take i and the parameters
and return the next and previous state variables respectively. The behavior where there is no more state left is arbitrary.
The "first" and "last" functions must take the additional parameters and return the initial and last state variables respectively.
The created object is an iterator of class recursiveiter, which inherits
abstractiter and iter.
It can be used with foreach and accepts as.list conversion.
Usage
recursiveiter(nextFunc, prevFunc, firstFunc, lastFunc, ...)
Arguments
nextFunc, prevFunc |
Functions that take the iterator state and the parameters |
firstFunc, lastFunc |
Functions that take the parameters |
... |
additional parameters of the iterator |
Value
iterator object
Examples
fibiter <- recursiveiter(
nextFunc = function(i) if (length(i)==1 && i==0) 1 else
if (length(i)==1 && i==1) c(1,1) else
c(sum(i), i[1]),
prevFunc = NULL, firstFunc = function() 0, lastFunc = function() Inf)
for (k in 1:20) cat(nextElem(fibiter)[1], "")
Objects exported from other packages
Description
These objects are imported from other packages. Follow the links below to see their documentation.