A port of Python's excellent itertools module to R for efficient looping.
The R package itertools2
is a port of Python's excellent itertools
module to R for efficient
looping and is a replacement for the existing itertools R
package.
You can install the stable version on CRAN:
install.packages('itertools2', dependencies=TRUE)
If you prefer to download the latest version, instead run the following after installing devtools:
devtools::install_github('ramhiser/itertools2')
The itertools2
R package is licensed under the MIT
License. However, this package depends on the iterators R
package,
which is licensed under the Apache License, Version
2.0. Both packages are freely
available for commercial and non-commerical usage. Please consult the licensing
terms for more details.
ichunk()
: Iterator that returns elements in fixed-length chunks. If the
length of the iterator is not divisible by chunk_size
, the remainder of the
last block is filled with the value specified in fill
.
ipad()
: Iterator that returns an object followed indefinitely by a fill
value.
ipairwise()
: Iterator that returns elements of an object in pairs.
iroundrobin()
: Iterator that traverses each given iterable in a roundrobin
order.
itabulate()
: Iterator that maps a function to a sequence of numeric values.
iunique()
: Iterator that extracts the unique elements from an iterable
object. This function is an iterator analogue to base::unique.
iunique_justseen()
: Iterator that extracts the just-seen unique elements
from an iterable object. Only the element just seen is remembered for
determining uniqueness.
consume()
: Consumes the first n elements of an iterator.
dotproduct()
: Computes the dot product of two iterable objects.
iter_deepcopy()
: Performs a deep copy of an iterator.
nth()
: Returns the nth item of an iterator, skipping the iterator ahead
during the process. If the iterator is entirely consumed, a default value is
returned.
quantify()
: Count the number of times an iterable object is TRUE.
take()
: Return the first n elements of an iterable object as a list.
Fixed a rare issue where ichain()
was throwing an uncaught exception.
Resolved an issue with itee()
when applied to an iterator. Shallow copies
were being made, such that each shared a common state
. The introduction of
iter_deepcopy()
resolved this issue, closing Issue #36.
ichain()
: Chains multiple arguments together into a single iterator.
Generates an iterator that returns elements from the first argument until it
is exhausted. Then generates an iterator from the next argument and returns
elements from it. This process continues until all arguments are exhausted.
Chaining is useful for treating consecutive sequences as a single sequence.
icompress()
: Iterator that filters elements where corresponding selector is
false. Returns only those elements for which the corresponding 'selector' is
TRUE
.
icount()
: Neverending numeric sequence with initial value and step size.
icycle()
: Iterator that cycles indefinitely through an iterable object
idropwhile()
: Iterator that drops elements until the predicate function
returns FALSE
.
ienum()
: Alias to ienumerate()
to save a few keystrokes.
ienumerate()
: Iterator that returns the elements of an object along with
their indices. This function is intended to follow the convention used in
Python's enumerate
function.
ifilter()
: Iterator that filters elements not satisfying a predicate
function. Returns only those elements for which the predicate function is
TRUE
.
ifilterfalse()
: Iterator that filters elements not satisfying a predicate
function. Returns only those elements for which the predicate function is
FALSE
.
imap()
: Iterator that applies a given function to several iterables
concurrently.
iproduct()
: Iterator that returns the Cartesian product of the
arguments. Similar to base::expand.grid()
.
irep()
: Iterator that replicates elements of an iterable object. Follows the
base::rep()
function.
irep_len()
: Iterator that replicates elements of an iterable object with a
desired length. Follows the base::rep_len()
function.
irepeat()
: Iterator that returns an object indefinitely unless a specified
number of times is given.
iseq()
: Iterator for sequence generation. Follows the base seq()
function.
iseq_along()
: Iterators for sequence generation of length equal to an
object. Follows the base::seq_along()
function.
iseq_len()
: Iterators for sequence generation of a fixed length. Follows the
base::seq_len()
function.
islice()
: Iterator that returns selected elements from an iterable.
istar()
: Alias to istarmap()
to save a few keystrokes.
istarmap()
: Iterator that applies a given function to the elements of an
iterable.
itakewhile()
: Iterator that returns elements while a predicate function
returns TRUE
.
itee()
: Returns a list of n independent iterators from a single iterable
object.
izip()
: Iterator that iterates through several iterables concurrently.
izip_longest()
: Iterator that iterates through several iterables
concurrently. Missing values are replaced with the value given in fill
if
the iterables are of uneven length.