def read_partition(fs,
piece,
columns,
index,
categories=(),
pf=None,
**kwargs):
if isinstance(index, list):
columns += index
if pf is None:
base, fns = _analyze_paths([piece], fs)
scheme = get_file_scheme(fns)
pf = ParquetFile(piece, open_with=fs.open)
relpath = piece.replace(base, "").lstrip("/")
for rg in pf.row_groups:
for ch in rg.columns:
ch.file_path = relpath
pf.file_scheme = scheme
pf.cats = _paths_to_cats(fns, scheme)
pf.fn = base
return pf.to_pandas(columns, categories, index=index)
else:
if isinstance(pf, tuple):
pf = _determine_pf_parts(fs, pf[0], pf[1], **kwargs)[1]
pf._dtypes = lambda *args: pf.dtypes # ugly patch, could be fixed
pf.fmd.row_groups = None
rg_piece = pf.row_groups[piece]
pf.fmd.key_value_metadata = None
return pf.read_row_group_file(rg_piece,
columns,
categories,
index=index,
**kwargs.get("read", {}))
def read_partition(
cls, fs, piece, columns, index, categories=(), pf=None, **kwargs
):
null_index_name = False
if isinstance(index, list):
if index == [None]:
# Handling a None-labeled index...
# The pandas metadata told us to read in an index
# labeled `None`. If this corresponds to a `RangeIndex`,
# fastparquet will need use the pandas metadata to
# construct the index. Otherwise, the index will correspond
# to a column named "__index_level_0__". We will need to
# check the `ParquetFile` object for this column below.
index = []
null_index_name = True
columns += index
if pf is None:
base, fns = _analyze_paths([piece], fs)
scheme = get_file_scheme(fns)
pf = ParquetFile(piece, open_with=fs.open)
relpath = piece.replace(base, "").lstrip("/")
for rg in pf.row_groups:
for ch in rg.columns:
ch.file_path = relpath
pf.file_scheme = scheme
pf.cats = paths_to_cats(fns, scheme)
pf.fn = base
if null_index_name and "__index_level_0__" in pf.columns:
# See "Handling a None-labeled index" comment above
index = ["__index_level_0__"]
columns += index
return pf.to_pandas(columns, categories, index=index)
else:
if isinstance(pf, tuple):
if isinstance(pf[0], list):
pf = _determine_pf_parts(fs, pf[0], pf[1], **kwargs)[1]
else:
pf = ParquetFile(
pf[0], open_with=fs.open, sep=fs.sep, **kwargs.get("file", {})
)
pf._dtypes = lambda *args: pf.dtypes # ugly patch, could be fixed
pf.fmd.row_groups = None
rg_piece = pf.row_groups[piece]
if null_index_name:
if "__index_level_0__" in pf.columns:
# See "Handling a None-labeled index" comment above
index = ["__index_level_0__"]
columns += index
pf.fmd.key_value_metadata = None
else:
pf.fmd.key_value_metadata = None
return pf.read_row_group_file(
rg_piece, columns, categories, index=index, **kwargs.get("read", {})
)
def read_partition(cls, fs, piece, columns, index, categories=(),
**kwargs):
null_index_name = False
if isinstance(index, list):
if index == [None]:
# Handling a None-labeled index...
# The pandas metadata told us to read in an index
# labeled `None`. If this corresponds to a `RangeIndex`,
# fastparquet will need use the pandas metadata to
# construct the index. Otherwise, the index will correspond
# to a column named "__index_level_0__". We will need to
# check the `ParquetFile` object for this column below.
index = []
null_index_name = True
columns += index
# Use global `parquet_file` object. Need to reattach
# the desired row_group
parquet_file = kwargs.pop("parquet_file", None)
if isinstance(piece, tuple):
if isinstance(piece[0], str):
# We have a path to read from
assert parquet_file is None
parquet_file = ParquetFile(piece[0],
open_with=fs.open,
sep=fs.sep,
**kwargs.get("file", {}))
rg_indices = piece[1] or list(
range(len(parquet_file.row_groups)))
# `piece[1]` will contain row-group indices
row_groups = [parquet_file.row_groups[rg] for rg in rg_indices]
elif parquet_file:
# `piece[1]` will contain actual row-group objects,
# but they may be pickled
row_groups = piece[0]
if isinstance(row_groups, bytes):
row_groups = pickle.loads(row_groups)
parquet_file.fmd.row_groups = row_groups
# NOTE: May lose cats after `_set_attrs` call
save_cats = parquet_file.cats
parquet_file._set_attrs()
parquet_file.cats = save_cats
else:
raise ValueError("Neither path nor ParquetFile detected!")
if null_index_name:
if "__index_level_0__" in parquet_file.columns:
# See "Handling a None-labeled index" comment above
index = ["__index_level_0__"]
columns += index
parquet_file._dtypes = (lambda *args: parquet_file.dtypes
) # ugly patch, could be fixed
# Read necessary row-groups and concatenate
dfs = []
for row_group in row_groups:
dfs.append(
parquet_file.read_row_group_file(
row_group,
columns,
categories,
index=index,
**kwargs.get("read", {}),
))
return concat(dfs, axis=0) if len(dfs) > 1 else dfs[0]
else:
# `piece` is NOT a tuple
raise ValueError(f"Expected tuple, got {type(piece)}")
def read_partition(
cls,
fs,
pieces,
columns,
index,
categories=(),
root_cats=None,
root_file_scheme=None,
base_path=None,
**kwargs,
):
null_index_name = False
base_path = False if not root_cats else base_path
if isinstance(index, list):
if index == [None]:
# Handling a None-labeled index...
# The pandas metadata told us to read in an index
# labeled `None`. If this corresponds to a `RangeIndex`,
# fastparquet will need use the pandas metadata to
# construct the index. Otherwise, the index will correspond
# to a column named "__index_level_0__". We will need to
# check the `ParquetFile` object for this column below.
index = []
null_index_name = True
columns += index
# Use global `parquet_file` object. Need to reattach
# the desired row_group
parquet_file = kwargs.pop("parquet_file", None)
# Always convert pieces to list
if not isinstance(pieces, list):
pieces = [pieces]
sample = pieces[0]
if isinstance(sample, tuple):
if isinstance(sample[0], str):
# We have paths to read from
assert parquet_file is None
row_groups = []
rg_offset = 0
parquet_file = ParquetFile(
[p[0] for p in pieces],
open_with=fs.open,
root=base_path or False,
**kwargs.get("file", {}),
)
for piece in pieces:
_pf = (parquet_file if len(pieces) == 1 else ParquetFile(
piece[0],
open_with=fs.open,
root=base_path or False,
**kwargs.get("file", {}),
))
n_local_row_groups = len(_pf.row_groups)
local_rg_indices = piece[1] or list(
range(n_local_row_groups))
row_groups += [
parquet_file.row_groups[rg + rg_offset]
for rg in local_rg_indices
]
rg_offset += n_local_row_groups
update_parquet_file = len(row_groups) < len(
parquet_file.row_groups)
elif parquet_file:
row_groups = []
for piece in pieces:
# `piece[1]` will contain actual row-group objects,
# but they may be pickled
rgs = piece[0]
if isinstance(rgs, bytes):
rgs = pickle.loads(rgs)
row_groups += rgs
update_parquet_file = True
else:
raise ValueError("Neither path nor ParquetFile detected!")
if update_parquet_file:
with _FP_FILE_LOCK:
parquet_file.fmd.row_groups = row_groups
# NOTE: May lose cats after `_set_attrs` call
save_cats = parquet_file.cats
parquet_file._set_attrs()
parquet_file.cats = save_cats
if null_index_name:
if "__index_level_0__" in parquet_file.columns:
# See "Handling a None-labeled index" comment above
index = ["__index_level_0__"]
columns += index
# Update hive-partitioning information if necessary
parquet_file.cats = root_cats or {}
if root_cats:
parquet_file.file_scheme = root_file_scheme
parquet_file._dtypes = (lambda *args: parquet_file.dtypes
) # ugly patch, could be fixed
if set(columns).issubset(parquet_file.columns +
list(parquet_file.cats.keys())):
# Convert ParquetFile to pandas
return parquet_file.to_pandas(
columns=columns,
categories=categories,
index=index,
)
else:
# Read necessary row-groups and concatenate
dfs = []
for row_group in row_groups:
dfs.append(
parquet_file.read_row_group_file(
row_group,
columns,
categories,
index=index,
**kwargs.get("read", {}),
))
return concat(dfs, axis=0) if len(dfs) > 1 else dfs[0]
else:
# `sample` is NOT a tuple
raise ValueError(f"Expected tuple, got {type(sample)}")
