Index of iteror functions by task

Basic methods

• is.iteror – Check whether a function has class ‘iteror’.
• iteror – Generic function to convert a given object into an iteror.
• nextOr – Obtain the next element from an iteror.
• r_to_py.iteror – Make an iteror act as a Python iterator (requires package reticulate)

Consuming / summarizing an iteror

Most of these functions are S3 generic.

• as.character, as.numeric, as.logical, as.list – Collect all an iteror’s values into a vector.
• as.vector – Collect values into a specified type of vector.
• concat – Paste an iteror’s values end-to-end in one vector.
• consume – Take all or some of an iteror’s elements and discard them.
• count – Compute all elements, discard them and return their count.
• dotproduct – Sum of products of corresponding elements of two iterors.
• nth – Compute and discard the first \(n-1\) elements and return the \(n\)th.
• prod.iteror – Product of all an iteror’s values (i.e. reduce using *.)
• quantify – Consume an iteror and return how many elements were TRUE.
• record – Write an iteror’s elements to a file.
• reduce – Combine all of iteror’s values in sequence using a 2-argument function, returning the final value.
• sum.iteror – Sum all values of an iteror (i.e. reduce using +.)
• take – Take some number of elements and return them in a vector.

Iterate over given data

By convention, functions in this package that construct an iterator in terms of basic data or other objects have names beginning with “i”.

• ienum, ienumerate – return the elements of an iterable alongside its index.
• i_enumerate – return the elements of a vector or array alongside indices, optionally chunked or recycled.
• i_repeat – Return one value over and over again.
• iteror.array – Iterate over an array along given dimensions.
• iteror.data.frame – Iterate over rows or columns of a data frame.
• iteror.default – Iterate over a vector from first to last index.

Counting or other mathematically defined processes

• i_combinations – Enumerate all combinations of \(m\) elements of a given vector, with or without replacement.
• i_count – Produce an integer sequence starting with 1.
• i_countn – Enumerate multiple indices, in either row-major or col-major order.
• i_div – Return a sequence of \(n\) integers that add up to a given total.
• i_grid – Produce a sequence over the Cartesian product of the given vectors.
• i_permutations – A sequence containing all permutations of a given vector.
• i_seq – Generate arithmetic sequences with specific step size and origin.
• i_seq_along – Counting sequence parallel to a given vector.

Random number generation

Random number iterators can be made reproducible by specifying independent=TRUE and specifying a seed value, though this has a performance cost.

• i_RNGStream, i_RNGSubStream – Create a sequence of seed values so as to make parallel, decorrelated random streams.
• i_rnbinom, irnorm, i_rpois, irunif, i_sample, irbinom – Draw samples from the given distribution.

Iterators dealing with files or functions

• i_read.table – Reads row-wise from delimited text files.
• i_readBin – Read binary data from file connections.
• i_readLines – Read lines from text connections.
• i_readdf – Read rows from several files in parallel (one per column).
• i_replay – reads back values from a data file created with record
• i_tabulate – Evaluate a function over an arithmetic sequence.
• record – Write values from an iterator to a file.

Custom iterators

• iteror.function – Create an iteror with custom behavior.

Higher order iterator functions

By convention, in this package, functions that transform iterators – creating a new iterator based on one or more underlying iterables – begin with “i_”, with an underscore.