def __init__(self, variable, index=slice(None)):
"""
Initializer
Parameters:
variable (VariableDesc): A variable descriptor object
index (tuple, slice, int, dict): A tuple of slices or ints, or a slice or int,
specifying the range of data to read from the file (in file-local indices)
"""
# Check variable descriptor type and existence in the file
if not isinstance(variable, VariableDesc):
raise TypeError('Unrecognized variable descriptor of type '
'{!r}: {!r}'.format(type(variable), variable.name))
# Check for associated file
if len(variable.files) == 0:
raise ValueError(
'Variable descriptor {} has no associated files'.format(
variable.name))
self._filepath = None
for fdesc in variable.files.itervalues():
if fdesc.exists():
self._filepath = fdesc.name
break
if self._filepath is None:
raise OSError(
'File path not found for input variable: {!r}'.format(
variable.name))
# Check that the variable exists in the file
with Dataset(self._filepath, 'r') as ncfile:
if variable.name not in ncfile.variables:
raise OSError(
'Variable {!r} not found in NetCDF file: {!r}'.format(
variable.name, self._filepath))
self._variable = variable.name
# Check if the index means "all"
is_all = False
if isinstance(index, slice) and index == slice(None):
is_all = True
elif isinstance(index, (list, tuple)) and all(i == slice(None)
for i in index):
is_all = True
elif isinstance(index, dict) and all(v == slice(None)
for v in index.itervalues()):
is_all = True
# Store the reading index
self._index = index
# Call the base class initializer
if is_all:
label = variable.name
else:
label = '{}[{}]'.format(variable.name, index_str(index))
super(ReadNode, self).__init__(label)
def test_index_str_dict(self):
indata = {'x': 4, 'y': slice(3, 1, -4)}
testname = 'index_str({!r})'.format(indata)
actual = index_str(indata)
expected = "'x': 4, 'y': 3:1:-4"
print_test_message(testname,
indata=indata,
actual=actual,
expected=expected)
self.assertEqual(actual, expected, '{} failed'.format(testname))
def test_index_str_tuple(self):
indata = (4, slice(3, 1, -4))
testname = 'index_str({!r})'.format(indata)
actual = index_str(indata)
expected = '4, 3:1:-4'
print_test_message(testname,
indata=indata,
actual=actual,
expected=expected)
self.assertEqual(actual, expected, '{} failed'.format(testname))
def test_index_str_slice(self):
indata = slice(1, 2, 3)
testname = 'index_str({!r})'.format(indata)
actual = index_str(indata)
expected = '1:2:3'
print_test_message(testname,
indata=indata,
actual=actual,
expected=expected)
self.assertEqual(actual, expected, '{} failed'.format(testname))
def test_index_str_int(self):
indata = 3
testname = 'index_str({!r})'.format(indata)
actual = index_str(indata)
expected = str(indata)
print_test_message(testname,
indata=indata,
actual=actual,
expected=expected)
self.assertEqual(actual, expected, '{} failed'.format(testname))
