def __init__(self, input, transposed=True):
"""
Initialize the matrix reader.
The `input` refers to a file on local filesystem, which is expected to
be in the sparse (coordinate) Matrix Market format. Documents are assumed
to be rows of the matrix (and document features are columns).
`input` is either a string (file path) or a file-like object that supports
`seek()` (e.g. gzip.GzipFile, bz2.BZ2File).
"""
logger.info("initializing corpus reader from %s" % input)
self.input, self.transposed = input, transposed
with utils.file_or_filename(self.input) as lines:
try:
header = utils.to_unicode(next(lines)).strip()
if not header.lower().startswith('%%matrixmarket matrix coordinate real general'):
raise ValueError("File %s not in Matrix Market format with coordinate real general; instead found: \n%s" %
(self.input, header))
except StopIteration:
pass
self.num_docs = self.num_terms = self.num_nnz = 0
for lineno, line in enumerate(lines):
line = utils.to_unicode(line)
if not line.startswith('%'):
self.num_docs, self.num_terms, self.num_nnz = map(int, line.split())
if not self.transposed:
self.num_docs, self.num_terms = self.num_terms, self.num_docs
break
logger.info("accepted corpus with %i documents, %i features, %i non-zero entries" %
(self.num_docs, self.num_terms, self.num_nnz))
def __iter__(self):
"""
Iteratively yield vectors from the underlying file, in the format (row_no, vector),
where vector is a list of (col_no, value) 2-tuples.
Note that the total number of vectors returned is always equal to the
number of rows specified in the header; empty documents are inserted and
yielded where appropriate, even if they are not explicitly stored in the
Matrix Market file.
"""
with utils.file_or_filename(self.input) as lines:
self.skip_headers(lines)
previd = -1
for line in lines:
docid, termid, val = utils.to_unicode(
line).split() # needed for python3
if not self.transposed:
termid, docid = docid, termid
docid, termid, val = int(docid) - 1, int(termid) - 1, float(
val
) # -1 because matrix market indexes are 1-based => convert to 0-based
assert previd <= docid, "matrix columns must come in ascending order"
if docid != previd:
# change of document: return the document read so far (its id is prevId)
if previd >= 0:
yield previd, document
# return implicit (empty) documents between previous id and new id
# too, to keep consistent document numbering and corpus length
for previd in xrange(previd + 1, docid):
yield previd, []
# from now on start adding fields to a new document, with a new id
previd = docid
document = []
document.append((
termid,
val,
)) # add another field to the current document
# handle the last document, as a special case
if previd >= 0:
yield previd, document
# return empty documents between the last explicit document and the number
# of documents as specified in the header
for previd in xrange(previd + 1, self.num_docs):
yield previd, []
def __iter__(self):
"""
Iteratively yield vectors from the underlying file, in the format (row_no, vector),
where vector is a list of (col_no, value) 2-tuples.
Note that the total number of vectors returned is always equal to the
number of rows specified in the header; empty documents are inserted and
yielded where appropriate, even if they are not explicitly stored in the
Matrix Market file.
"""
with utils.file_or_filename(self.input) as lines:
self.skip_headers(lines)
previd = -1
for line in lines:
docid, termid, val = utils.to_unicode(line).split() # needed for python3
if not self.transposed:
termid, docid = docid, termid
docid, termid, val = int(docid) - 1, int(termid) - 1, float(
val) # -1 because matrix market indexes are 1-based => convert to 0-based
assert previd <= docid, "matrix columns must come in ascending order"
if docid != previd:
# change of document: return the document read so far (its id is prevId)
if previd >= 0:
yield previd, document
# return implicit (empty) documents between previous id and new id
# too, to keep consistent document numbering and corpus length
for previd in xrange(previd + 1, docid):
yield previd, []
# from now on start adding fields to a new document, with a new id
previd = docid
document = []
document.append((termid, val,)) # add another field to the current document
# handle the last document, as a special case
if previd >= 0:
yield previd, document
# return empty documents between the last explicit document and the number
# of documents as specified in the header
for previd in xrange(previd + 1, self.num_docs):
yield previd, []
def __init__(self, input, transposed=True):
"""
Initialize the matrix reader.
The `input` refers to a file on local filesystem, which is expected to
be in the sparse (coordinate) Matrix Market format. Documents are assumed
to be rows of the matrix (and document features are columns).
`input` is either a string (file path) or a file-like object that supports
`seek()` (e.g. gzip.GzipFile, bz2.BZ2File).
"""
logger.info("initializing corpus reader from %s" % input)
self.input, self.transposed = input, transposed
with utils.file_or_filename(self.input) as lines:
try:
header = utils.to_unicode(next(lines)).strip()
if not header.lower().startswith(
'%%matrixmarket matrix coordinate real general'):
raise ValueError(
"File %s not in Matrix Market format with coordinate real general; instead found: \n%s"
% (self.input, header))
except StopIteration:
pass
self.num_docs = self.num_terms = self.num_nnz = 0
for lineno, line in enumerate(lines):
line = utils.to_unicode(line)
if not line.startswith('%'):
self.num_docs, self.num_terms, self.num_nnz = map(
int, line.split())
if not self.transposed:
self.num_docs, self.num_terms = self.num_terms, self.num_docs
break
logger.info(
"accepted corpus with %i documents, %i features, %i non-zero entries"
% (self.num_docs, self.num_terms, self.num_nnz))
