itertools package provides a variety of functions used to create
iterators, as defined by REvolution Computing's iterators package.
Many of the functions are patterned after functions of the same name in
the Python itertools module, including chain, product,
izip, ifilter, etc.
In addition, a number of functions were inspired by utility functions in the
snow package, such as isplitRows, isplitCols, and
isplitIndices.There are also several utility functions that were contributed by
Hadley Wickham that aid in writing iterators.
These include is.iterator, end_iterator,
iteration_has_ended, and new_iterator.
isplitVector |
| splits, or slices, a vector into shorter segments |
isplitCols |
| splits a matrix column-wise |
isplitRows |
| splits a matrix row-wise |
isplitIndices |
| iterate over “chunks” of indices from 1 to n |
chain |
| chain multiple iterators together into one iterator |
enumerate |
| create an enumeration from an iterator |
ichunk |
| create lists of values from an iterator to aid manual chunking |
ihasNext |
| add a hasNext method to an iterator |
ifilter |
| only return values for which a predicate function returns true |
ifilterfalse |
| only return values for which a predicate function returns false |
ilimit |
| limit, or truncate, an iterator |
ireadBin |
| reads from a binary connection |
irep |
| an iterator version of the rep function |
irepeat |
| a simple repeating value iterator |
izip |
| zip together multiple iterators |
product |
| zip together multiple iterators in cartesian product fashion |
recycle |
| recycle values from an iterator repeatedly |
timeout |
| iterate for a specified number of seconds |
is.iterator |
| indicates if an object is an iterator |
end_iteration |
| throws an exception to signal end of iteration |
iteration_has_ended |
| tests an exception to see if iteration has ended |
new_iterator |
| creates a new iterator object |
For a complete list of functions with individual help pages,
use library(help="itertools").