def __getitem__(self, index):
"Allows use of the index [] operator to get a layer at the index."
if isinstance(index, basestring):
l = capi.get_layer_by_name(self.ptr, index)
if not l: raise OGRIndexError('invalid OGR Layer name given: "%s"' % index)
elif isinstance(index, int):
if index < 0 or index >= self.layer_count:
raise OGRIndexError('index out of range')
l = capi.get_layer(self._ptr, index)
else:
raise TypeError('Invalid index type: %s' % type(index))
return Layer(l, self)
def index(self, field_name):
"Returns the index of the given field name."
i = capi.get_field_index(self.ptr, field_name)
if i < 0:
raise OGRIndexError('invalid OFT field name given: "%s"' %
field_name)
return i
def __getitem__(self, index):
"""
Gets the Field object at the specified index, which may be either
an integer or the Field's string label. Note that the Field object
is not the field's _value_ -- use the `get` method instead to
retrieve the value (e.g. an integer) instead of a Field instance.
"""
if isinstance(index, basestring):
i = self.index(index)
else:
if index < 0 or index > self.num_fields:
raise OGRIndexError('index out of range')
i = index
return Field(self.ptr, i)
def __getitem__(self, index):
"Returns the Point at the given index."
if index >= 0 and index < self.point_count:
x, y, z = c_double(), c_double(), c_double()
capi.get_point(self.ptr, index, byref(x), byref(y), byref(z))
dim = self.coord_dim
if dim == 1:
return (x.value,)
elif dim == 2:
return (x.value, y.value)
elif dim == 3:
return (x.value, y.value, z.value)
else:
raise OGRIndexError('index out of range: %s' % str(index))
def __getitem__(self, index):
"Gets the Feature at the specified index."
if isinstance(index, (int, long)):
# An integer index was given -- we cannot do a check based on the
# number of features because the beginning and ending feature IDs
# are not guaranteed to be 0 and len(layer)-1, respectively.
if index < 0:
raise OGRIndexError(
'Negative indices are not allowed on OGR Layers.')
return self._make_feature(index)
elif isinstance(index, slice):
# A slice was given
start, stop, stride = index.indices(self.num_feat)
return [
self._make_feature(fid) for fid in xrange(start, stop, stride)
]
else:
raise TypeError(
'Integers and slices may only be used when indexing OGR Layers.'
)
def _make_feature(self, feat_id):
"""
Helper routine for __getitem__ that constructs a Feature from the given
Feature ID. If the OGR Layer does not support random-access reading,
then each feature of the layer will be incremented through until the
a Feature is found matching the given feature ID.
"""
if self._random_read:
# If the Layer supports random reading, return.
try:
return Feature(capi.get_feature(self.ptr, feat_id),
self._ldefn)
except OGRException:
pass
else:
# Random access isn't supported, have to increment through
# each feature until the given feature ID is encountered.
for feat in self:
if feat.fid == feat_id: return feat
# Should have returned a Feature, raise an OGRIndexError.
raise OGRIndexError('Invalid feature id: %s.' % feat_id)
def __getitem__(self, index):
"Gets the Geometry at the specified index."
if index < 0 or index >= self.geom_count:
raise OGRIndexError('index out of range: %s' % index)
else:
return OGRGeometry(capi.clone_geom(capi.get_geom_ref(self.ptr, index)), self.srs)