def join(keys, tables):
"""Merge a list of `Table` objects using `keys` to group rows"""
# Make new (merged) Table fields
fields = OrderedDict()
for table in tables:
fields.update(table.fields)
# TODO: may raise an error if a same field is different in some tables
# Check if all keys are inside merged Table's fields
fields_keys = set(fields.keys())
for key in keys:
if key not in fields_keys:
raise ValueError('Invalid key: "{}"'.format(key))
# Group rows by key, without missing ordering
none_fields = lambda: OrderedDict({field: None for field in fields.keys()})
data = OrderedDict()
for table in tables:
for row in table:
row_key = tuple([getattr(row, key) for key in keys])
if row_key not in data:
data[row_key] = none_fields()
data[row_key].update(row._asdict())
merged = Table(fields=fields)
merged.extend(data.values())
return merged
def join(keys, tables):
"""Merge a list of `Table` objects using `keys` to group rows"""
# Make new (merged) Table fields
fields = OrderedDict()
for table in tables:
fields.update(table.fields)
# TODO: may raise an error if a same field is different in some tables
# Check if all keys are inside merged Table's fields
fields_keys = set(fields.keys())
for key in keys:
if key not in fields_keys:
raise ValueError('Invalid key: "{}"'.format(key))
# Group rows by key, without missing ordering
none_fields = lambda: OrderedDict({field: None for field in fields.keys()})
data = OrderedDict()
for table in tables:
for row in table:
row_key = tuple([getattr(row, key) for key in keys])
if row_key not in data:
data[row_key] = none_fields()
data[row_key].update(row._asdict())
merged = Table(fields=fields)
merged.extend(data.values())
return merged
def create_table(data,
meta=None,
fields=None,
skip_header=True,
import_fields=None,
samples=None,
force_types=None,
*args,
**kwargs):
"""Create a rows.Table object based on data rows and some configurations
- `skip_header` is only used if `fields` is set
- `samples` is only used if `fields` is `None`. If samples=None, all data
is filled in memory - use with caution.
- `force_types` is only used if `fields` is `None`
- `import_fields` can be used either if `fields` is set or not, the
resulting fields will seek its order
- `fields` must always be in the same order as the data
"""
table_rows = iter(data)
force_types = force_types or {}
if import_fields is not None:
import_fields = make_header(import_fields)
if fields is None: # autodetect field types
# TODO: may add `type_hints` parameter so autodetection can be easier
# (plugins may specify some possible field types).
header = make_header(next(table_rows))
if samples is not None:
sample_rows = list(islice(table_rows, 0, samples))
table_rows = chain(sample_rows, table_rows)
else:
sample_rows = table_rows = list(table_rows)
# Detect field types using only the desired columns
detected_fields = detect_types(
header,
sample_rows,
skip_indexes=[
index for index, field in enumerate(header)
if field in force_types or field not in (
import_fields or header)
],
*args,
**kwargs)
# Check if any field was added during detecting process
new_fields = [
field_name for field_name in detected_fields.keys()
if field_name not in header
]
# Finally create the `fields` with both header and new field names,
# based on detected fields `and force_types`
fields = OrderedDict([(field_name,
detected_fields.get(field_name, TextField))
for field_name in header + new_fields])
fields.update(force_types)
# Update `header` and `import_fields` based on new `fields`
header = list(fields.keys())
if import_fields is None:
import_fields = header
else: # using provided field types
if not isinstance(fields, OrderedDict):
raise ValueError("`fields` must be an `OrderedDict`")
if skip_header:
# If we're skipping the header probably this row is not trustable
# (can be data or garbage).
_ = next(table_rows)
header = make_header(list(fields.keys()))
if import_fields is None:
import_fields = header
fields = OrderedDict([(field_name, fields[key])
for field_name, key in zip(header, fields)])
diff = set(import_fields) - set(header)
if diff:
field_names = ", ".join('"{}"'.format(field) for field in diff)
raise ValueError("Invalid field names: {}".format(field_names))
fields = OrderedDict([(field_name, fields[field_name])
for field_name in import_fields])
get_row = get_items(*map(header.index, import_fields))
table = Table(fields=fields, meta=meta)
table.extend(dict(zip(import_fields, get_row(row))) for row in table_rows)
return table
def create_table(
data,
meta=None,
fields=None,
skip_header=True,
import_fields=None,
samples=None,
force_types=None,
*args,
**kwargs
):
"""Create a rows.Table object based on data rows and some configurations
- `skip_header` is only used if `fields` is set
- `samples` is only used if `fields` is `None`. If samples=None, all data
is filled in memory - use with caution.
- `force_types` is only used if `fields` is `None`
- `import_fields` can be used either if `fields` is set or not, the
resulting fields will seek its order
- `fields` must always be in the same order as the data
"""
table_rows = iter(data)
force_types = force_types or {}
if import_fields is not None:
import_fields = make_header(import_fields)
if fields is None: # autodetect field types
# TODO: may add `type_hints` parameter so autodetection can be easier
# (plugins may specify some possible field types).
header = make_header(next(table_rows))
if samples is not None:
sample_rows = list(islice(table_rows, 0, samples))
table_rows = chain(sample_rows, table_rows)
else:
sample_rows = table_rows = list(table_rows)
# Detect field types using only the desired columns
detected_fields = detect_types(
header,
sample_rows,
skip_indexes=[
index
for index, field in enumerate(header)
if field in force_types or field not in (import_fields or header)
],
*args,
**kwargs
)
# Check if any field was added during detecting process
new_fields = [
field_name
for field_name in detected_fields.keys()
if field_name not in header
]
# Finally create the `fields` with both header and new field names,
# based on detected fields `and force_types`
fields = OrderedDict(
[
(field_name, detected_fields.get(field_name, TextField))
for field_name in header + new_fields
]
)
fields.update(force_types)
# Update `header` and `import_fields` based on new `fields`
header = list(fields.keys())
if import_fields is None:
import_fields = header
else: # using provided field types
if not isinstance(fields, OrderedDict):
raise ValueError("`fields` must be an `OrderedDict`")
if skip_header:
# If we're skipping the header probably this row is not trustable
# (can be data or garbage).
_ = next(table_rows)
header = make_header(list(fields.keys()))
if import_fields is None:
import_fields = header
fields = OrderedDict(
[(field_name, fields[key]) for field_name, key in zip(header, fields)]
)
diff = set(import_fields) - set(header)
if diff:
field_names = ", ".join('"{}"'.format(field) for field in diff)
raise ValueError("Invalid field names: {}".format(field_names))
fields = OrderedDict(
[(field_name, fields[field_name]) for field_name in import_fields]
)
get_row = get_items(*map(header.index, import_fields))
table = Table(fields=fields, meta=meta)
table.extend(dict(zip(import_fields, get_row(row))) for row in table_rows)
return table
