pydicom.dataelem.DataElement¶
-
class
pydicom.dataelem.
DataElement
(tag, VR, value, file_value_tell=None, is_undefined_length=False, already_converted=False)¶ Contain and manipulate a DICOM Element.
Examples
While its possible to create a new
DataElement
directly and add it to aDataset
:>>> from pydicom import Dataset >>> elem = DataElement(0x00100010, 'PN', 'CITIZEN^Joan') >>> ds = Dataset() >>> ds.add(elem)
Its far more convenient to use a
Dataset
to add a newDataElement
, as the VR and tag are determined automatically from the DICOM dictionary:>>> ds = Dataset() >>> ds.PatientName = 'CITIZEN^Joan'
Empty DataElement objects (e.g. with VM = 0) show an empty string as value for text VRs and None for non-text (binary) VRs:
>>> ds = Dataset() >>> ds.PatientName = None >>> ds.PatientName ''
>>> ds.BitsAllocated = None >>> ds.BitsAllocated
>>> str(ds.BitsAllocated) 'None'
-
descripWidth
¶ For string display, this is the maximum width of the description field (default
35
).Type: int
-
is_retired
¶ For officially registered DICOM Data Elements this will be
True
if the retired status as given in the DICOM Standard, Part 6, Table 6-1 is ‘RET’. For private or unknown elements this will always beFalse
.Type: bool
-
is_undefined_length
¶ Indicates whether the length field for the element was
0xFFFFFFFFL
(ie undefined).Type: bool
-
keyword
¶ For officially registered DICOM Data Elements this will be the Keyword as given in Table 6-1. For private or unknown elements this will return an empty string
''
.Type: str
-
maxBytesToDisplay
¶ For string display, elements with values containing data which is longer than this value will display
"array of # bytes"
(default16
).Type: int
-
name
¶ For officially registered DICOM Data Elements this will be the Name as given in Table 6-1. For private elements known to pydicom this will be the Name in the format
'[name]'
. For unknown private elements this will be'Private Creator'
. For unknown elements this will return an empty string''
.Type: str
-
showVR
¶ For string display, include the element’s VR just before it’s value (default
True
).Type: bool
-
value
¶ The element’s stored value(s).
-
VM
¶ The Value Multiplicity of the element’s stored value(s).
Type: int
-
VR
¶ The element’s Value Representation.
Type: str
-
__init__
(tag, VR, value, file_value_tell=None, is_undefined_length=False, already_converted=False)¶ Create a new
DataElement
.Parameters: - tag (int or or str or list or tuple) – The DICOM (group, element) tag in any form accepted by
Tag()
such as[0x0010, 0x0010]
,(0x10, 0x10)
,0x00100010
, etc. - VR (str) – The 2 character DICOM value representation (see DICOM Standard, Part 5, Section 6.2).
- value –
The value of the data element. One of the following:
- a single string value
- a number
- a
list
ortuple
with all strings or all numbers - a multi-value string with backslash separator
- file_value_tell (int or None) – Used internally by
Dataset
to store the write position for theReplaceDataElementValue()
method. Default isNone
. - is_undefined_length (bool) – Used internally to store whether the length field for this element
was
0xFFFFFFFFL
, i.e. ‘undefined length’. Default isFalse
. - already_converted (bool) – Used to determine whether or not the element’s value requires
conversion to a value with VM > 1. Default is
False
.
- tag (int or or str or list or tuple) – The DICOM (group, element) tag in any form accepted by
Methods
__init__
(tag, VR, value[, file_value_tell, …])Create a new DataElement
.clear
()Clears the value, e.g. description
()Return the DICOM dictionary name for the element as str
.from_json
(dataset_class, tag, vr, value, …)Return a DataElement
from JSON.to_json
([bulk_data_threshold, …])Return a JSON representation of the DataElement
.to_json_dict
(bulk_data_element_handler, …)Return a dictionary representation of the DataElement
conforming to the DICOM JSON Model as described in the DICOM Standard, Part 18, Annex F.Attributes
VM
Return the value multiplicity of the element as int
.descripWidth
empty_value
Return the value for an empty element. is_empty
Return True
if the element has no value.is_raw
is_retired
Return the element’s retired status as bool
.keyword
Return the element’s keyword (if known) as str
.maxBytesToDisplay
name
Return the DICOM dictionary name for the element as str
.repval
Return a str
representation of the element’s value.showVR
value
Return the element’s value. -
VM
Return the value multiplicity of the element as
int
.
-
clear
()¶ Clears the value, e.g. sets it to the configured empty value.
New in version 1.4.
See
empty_value_for_VR()
.
-
description
()¶ Return the DICOM dictionary name for the element as
str
.
-
empty_value
¶ Return the value for an empty element.
New in version 1.4.
See
empty_value_for_VR()
for more information.Returns: The value this data element is assigned on decoding if it is empty. Return type: str or None
-
classmethod
from_json
(dataset_class, tag, vr, value, value_key, bulk_data_uri_handler=None)¶ Return a
DataElement
from JSON.New in version 1.3.
Parameters: - dataset_class (dataset.Dataset derived class) – Class used to create sequence items.
- tag (BaseTag or int) – The data element tag.
- vr (str) – The data element value representation.
- value (list) – The data element’s value(s).
- value_key (str or None) – Key of the data element that contains the value
(options:
{"Value", "InlineBinary", "BulkDataURI"}
) - bulk_data_uri_handler (callable or None) – Callable function that accepts the “BulkDataURI” of the JSON representation of a data element and returns the actual value of that data element (retrieved via DICOMweb WADO-RS)
Returns: Return type:
-
is_empty
¶ Return
True
if the element has no value.New in version 1.4.
-
is_retired
Return the element’s retired status as
bool
.
-
keyword
Return the element’s keyword (if known) as
str
.
-
name
Return the DICOM dictionary name for the element as
str
.
-
repval
¶ Return a
str
representation of the element’s value.
-
to_json
(bulk_data_threshold=1024, bulk_data_element_handler=None, dump_handler=None)¶ Return a JSON representation of the
DataElement
.New in version 1.3.
Parameters: - bulk_data_element_handler (callable or None) – Callable that accepts a bulk data element and returns the “BulkDataURI” for retrieving the value of the data element via DICOMweb WADO-RS
- bulk_data_threshold (int) – Size of base64 encoded data element above which a value will be provided in form of a “BulkDataURI” rather than “InlineBinary”. Ignored if no bulk data handler is given.
- dump_handler (callable, optional) – Callable function that accepts a
dict
and returns the serialized (dumped) JSON string (by default usesjson.dumps()
).
Returns: Mapping representing a JSON encoded data element
Return type: dict
See also
Dataset.to_json()
-
to_json_dict
(bulk_data_element_handler, bulk_data_threshold)¶ Return a dictionary representation of the
DataElement
conforming to the DICOM JSON Model as described in the DICOM Standard, Part 18, Annex F.New in version 1.4.
Parameters: - bulk_data_element_handler (callable or None) – Callable that accepts a bulk data element and returns the “BulkDataURI” for retrieving the value of the data element via DICOMweb WADO-RS
- bulk_data_threshold (int) – Size of base64 encoded data element above which a value will be provided in form of a “BulkDataURI” rather than “InlineBinary”. Ignored if no bulk data handler is given.
Returns: Mapping representing a JSON encoded data element
Return type: dict
-
value
Return the element’s value.
-