def to_csv(self, local_path=None, temp_file_compression=None, encoding=None, errors='strict',
write_header=True, csv_name=None, **csvargs):
"""
Outputs table to a CSV. Additional key word arguments are passed to ``csv.writer()``. So,
e.g., to override the delimiter from the default CSV dialect, provide the delimiter
keyword argument.
.. warning::
If a file already exists at the given location, it will be
overwritten.
`Args:`
local_path: str
The path to write the csv locally. If it ends in ".gz" or ".zip", the file will be
compressed. If not specified, a temporary file will be created and returned,
and that file will be removed automatically when the script is done running.
temp_file_compression: str
If a temp file is requested (ie. no ``local_path`` is specified), the compression
type for that file. Currently "None", "gzip" or "zip" are supported.
If a ``local_path`` is specified, this argument is ignored.
encoding: str
The CSV encoding type for `csv.writer()
<https://docs.python.org/2/library/csv.html#csv.writer/>`_
errors: str
Raise an Error if encountered
write_header: boolean
Include header in output
csv_name: str
If ``zip`` compression (either specified or inferred), the name of csv file
within the archive.
\**csvargs: kwargs
``csv_writer`` optional arguments
`Returns:`
str
The path of the new file
""" # noqa: W605
# If a zip archive.
if files.zip_check(local_path, temp_file_compression):
return self.to_zip_csv(archive_path=local_path,
encoding=encoding,
errors=errors,
write_header=write_header,
csv_name=csv_name,
**csvargs)
if not local_path:
suffix = '.csv' + files.suffix_for_compression_type(temp_file_compression)
local_path = files.create_temp_file(suffix=suffix)
# Create normal csv/.gzip
petl.tocsv(self.table,
source=local_path,
encoding=encoding,
errors=errors,
write_header=write_header,
**csvargs)
return local_path
def to_json(self, local_path=None, temp_file_compression=None, line_delimited=False):
"""
Outputs table to a JSON file
.. warning::
If a file already exists at the given location, it will be
overwritten.
`Args:`
local_path: str
The path to write the JSON locally. If it ends in ".gz", it will be
compressed first. If not specified, a temporary file will be created and returned,
and that file will be removed automatically when the script is done running.
temp_file_compression: str
If a temp file is requested (ie. no ``local_path`` is specified), the compression
type for that file. Currently "None" and "gzip" are supported.
If a ``local_path`` is specified, this argument is ignored.
line_delimited: bool
Whether the file will be line-delimited JSON (with a row on each line), or a proper
JSON file.
`Returns:`
str
The path of the new file
"""
if not local_path:
suffix = '.json' + files.suffix_for_compression_type(temp_file_compression)
local_path = files.create_temp_file(suffix=suffix)
# Note we don't use the much simpler petl.tojson(), since that method reads the whole
# table into memory before writing to file.
if files.is_gzip_path(local_path):
open_fn = gzip.open
mode = 'w+t'
else:
open_fn = open
mode = 'w'
with open_fn(local_path, mode) as file:
if not line_delimited:
file.write('[')
i = 0
for row in self:
if i:
if not line_delimited:
file.write(',')
file.write('\n')
i += 1
json.dump(row, file)
if not line_delimited:
file.write(']')
return local_path
def test_suffix_for_compression_type():
assert files.suffix_for_compression_type(None) == ''
assert files.suffix_for_compression_type('') == ''
assert files.suffix_for_compression_type('gzip') == '.gz'