text2vec (version 0.5.0)

ifiles: Creates iterator over text files from the disk

Description

The result of this function usually used in an itoken function.

Usage

ifiles(file_paths, reader = readLines)
idir(path, reader = readLines)
ifiles_parallel(file_paths, reader = readLines,
  n_chunks = foreach::getDoParWorkers())

Arguments

file_paths

character paths of input files

reader

function which will perform reading of text files from disk, which should take a path as its first argument. reader() function should return named character vector: elements of vector = documents, names of the elements = document ids which will be used in DTM construction. If user doesn't provide named character vector, document ids will be generated as file_name + line_number (assuming that each line is a document).

path

character path of directory. All files in the directory will be read.

n_chunks

integer, defines in how many chunks files will be processed. For example if you have 32 files, and n_chunks = 8, then for each 4 files will be created a job (for example document-term matrix construction). In case some parallel backend registered, each job will be evaluated in a separated thread (process) in parallel. So each such group of files will be processed in parallel and at the end all 8 results from will be combined.

See Also

itoken

Examples

# NOT RUN {
current_dir_files = list.files(path = ".", full.names = TRUE)
files_iterator = ifiles(current_dir_files)
parallel_files_iterator = ifiles_parallel(current_dir_files, n_chunks = 4)
it = itoken_parallel(parallel_files_iterator)
dtm = create_dtm(it, hash_vectorizer(2**16), type = 'dgTMatrix')
# }
# NOT RUN {
dir_files_iterator = idir(path = ".")
# }