Choice type

class pyasn1.type.univ.Choice(componentType=None, tagSet=tagSet(), subtypeSpec=ConstraintsIntersection(), sizeSpec=ConstraintsIntersection())

Create Choice type.

Choice objects are mutable and duck-type Python dict objects.

Parameters:
  • componentType (NamedType) – Object holding named ASN.1 types allowed within this collection
  • tagSet (TagSet) – Object representing non-default ASN.1 tag(s)
  • subtypeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 subtype constraint(s)
  • sizeSpec (ConstraintsIntersection) – Object representing collection size constraint

Note

The Choice type can only hold a single component at a time belonging to the list of allowed types.

clone(componentType=None, tagSet=tagSet(), subtypeSpec=ConstraintsIntersection())

Create a copy of a Choice type or object.

Any parameters to the clone() method will replace corresponding properties of the Choice object.

Parameters:
  • tagSet (TagSet) – Object representing non-default ASN.1 tag(s)
  • subtypeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 subtype constraint(s)
  • sizeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 size constraint(s)
Returns:

new instance of Choice type/value
subtype(componentType=None, implicitTag=Tag(), explicitTag=Tag(), subtypeSpec=ConstraintsIntersection())

Create a copy of a Choice type or object.

Any parameters to the subtype() method will be added to the corresponding properties of the Choice object.

Parameters:
  • tagSet (TagSet) – Object representing non-default ASN.1 tag(s)
  • subtypeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 subtype constraint(s)
  • sizeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 size constraint(s)
Returns:

new instance of Choice type/value
tagSet = TagSet((), )

Default TagSet object for Choice objects (untagged by default)

componentType = NamedTypes()

Default collection of ASN.1 types of component (e.g. NamedType) object representing ASN.1 type allowed within Choice type

subtypeSpec = ConstraintsIntersection()

Default ConstraintsIntersection object imposing size constraint on Choice objects

sizeSpec = ConstraintsIntersection(ValueSizeConstraint(1, 1))

Default ConstraintsIntersection object imposing size constraint on Choice objects

getComponentByName(name)

Returns Choice type component by name.

Equivalent to Python dict subscription operation (e.g. []).

Parameters:name (str) – Choice type component name
Returns:PyAsn1Item – a pyasn1 object
getComponentByPosition(idx)

Returns Choice type component by index.

Equivalent to Python sequence subscription operation (e.g. []).

Parameters:idx (int) – component index (zero-based)
Returns:PyAsn1Item – a PyASN1 object
getComponentByType(tagSet, innerFlag=False)

Returns Choice type component by ASN.1 tag.

Parameters:tagSet (TagSet) – Object representing ASN.1 tags
Returns:PyAsn1Item – a pyasn1 object
isSameTypeWith(other, matchTags=True, matchConstraints=True)

Examine Choice type for equality with other ASN.1 type.

ASN.1 tags (tag) and constraints (constraint) are examined when carrying out ASN.1 types comparison.

No Python inheritance relationship between PyASN1 objects is considered.

Parameters:other (a pyasn1 type object) – Class instance representing ASN.1 type.
Returns:bool – True if other is Choice type, False otherwise.
isSuperTypeOf(other, matchTags=True, matchConstraints=True)

Examine Choice type for subtype relationship with other ASN.1 type.

ASN.1 tags (tag) and constraints (constraint) are examined when carrying out ASN.1 types comparison.

No Python inheritance relationship between PyASN1 objects is considered.

Parameters:other (a pyasn1 type object) – Class instance representing ASN.1 type.
Returns:bool – True if other is a subtype of Choice type, False otherwise.
setComponentByName(name, value=NoValue(), verifyConstraints=True, matchTags=True, matchConstraints=True)

Assign Choice type component by name.

Equivalent to Python dict item assignment operation (e.g. []).

Parameters:
  • name (str) – Choice type component name
  • value (object or PyAsn1Item derivative) – A Python or pyasn1 object to assign
  • verifyConstraints (bool) – If False, skip constraints validation
  • matchTags (bool) – If False, skip component tags matching
  • matchConstraints (bool) – If False, skip component constraints matching
Returns:

self
setComponentByType(tagSet, value=NoValue(), verifyConstraints=True, matchTags=True, matchConstraints=True, innerFlag=False)

Assign Choice type component by ASN.1 tag.

Parameters:
  • tagSet (TagSet) – Object representing ASN.1 tags
  • value (object or PyAsn1Item derivative) – A Python or pyasn1 object to assign
  • verifyConstraints (bool) – If False, skip constraints validation
  • matchTags (bool) – If False, skip component tags matching
  • matchConstraints (bool) – If False, skip component constraints matching
  • innerFlag (bool) – If True, search for matching tagSet recursively.
Returns:

self
setComponentByPosition(idx, value=NoValue(), verifyConstraints=True, matchTags=True, matchConstraints=True)

Assign Choice type component by position.

Equivalent to Python sequence item assignment operation (e.g. []).

Parameters:
  • idx (int) – component index (zero-based)
  • value (object or PyAsn1Item derivative) – A Python or pyasn1 object to assign
  • verifyConstraints (bool) – If False, skip constraints validation
  • matchTags (bool) – If False, skip component tags matching
  • matchConstraints (bool) – If False, skip component constraints matching
Returns:

self
getComponent(innerFlag=0)

Return currently assigned component of the Choice object.

Returns:PyAsn1Item – a PyASN1 object
getName(innerFlag=False)

Return the name of currently assigned component of the Choice object.

Returns:str – Choice component name