blpapi.Element¶
-
class
blpapi.
Element
¶ Represents an item in a message.
An
Element
can represent:A single value of any data type supported by the Bloomberg API
An array of values
A sequence or a choice
The value(s) in an
Element
can be queried in a number of ways. For anElement
which represents a single value or an array of values use thegetValueAsBool()
etc. functions. For anElement
which represents a sequence or choice usegetElementAsBool()
etc. functions. In addition, for choices and sequences,hasElement()
andgetElement()
are useful.This example shows how to access the value of a scalar element
s
as a floating point number:f = s.getValueAsFloat()
Similarly, this example shows how to retrieve the third value in an array element
a
, as a floating point number:f = a.getValueAsFloat(2)
Use
numValues()
to determine the number of values available. For single values, it will return either0
or1
. For arrays it will return the actual number of values in the array.To retrieve values from a complex element types (sequences and choices) use the
getElementAs...()
family of methods. This example shows how to get the value of the elementcity
in the sequence elementaddress
:city = address.getElementAsString("city")
Note
getElementAsXYZ(name)
method is a shortcut togetElement(name).getValueAsXYZ()
.The value(s) of an
Element
can be set in a number of ways. For anElement
which represents a single value or an array of values use thesetValue()
orappendValue()
functions. For an element which represents a sequence or a choice use thesetElement()
functions.This example shows how to set the value of an
Element
s
:value=5 s.setValue(value)
This example shows how to append a value to an array element
a
:value=5 a.appendValue(value)
To set values in a complex element (a sequence or a choice) use the
setElement()
family of functions. This example shows how to set the value of the elementcity
in the sequence elementaddress
to a string:address.setElement("city", "New York")
Methods which specify an
Element
name accept name in two forms:Name
or a string. PassingName
is more efficient. However, it requires theName
to have been created in the global name table.The form which takes a string is less efficient but will not cause a new
Name
to be created in the global name table. Because all validElement
names will have already been placed in the global name table by the API if the supplied string cannot be found in the global name table the appropriate error or exception can be returned.The API will convert data types as long as there is no loss of precision involved.
Element
objects are always created by the API, never directly by the application.-
appendValue
(value)¶ Append the specified
value
to thisElement
s entries at the end.- Parameters
value – Value to append
- Raises
Exception – If this
Element
’s datatype can’t be initialized from the type of the specifiedvalue
, or if the current size of thisElement
(numValues()
) is equal to the maximum defined byelementDefinition().maxValues()
.
This method can process the following types of
value
without conversion:boolean
integers
float
string
datetypes (
datetime.time
,datetime.date
ordatetime.datetime
)
Any other
value
will be converted to a string withstr
function and then processed in the same way as stringvalue
.
-
elementDefinition
()¶ - Returns
Reference to the read-only element definition object that defines the properties of this elements value.
- Return type
-
elements
()¶ - Returns
Iterator over elements contained in this
Element
.- Raises
UnsupportedOperationException – If this
Element
is not a sequence.
-
getChoice
()¶
-
getElement
(nameOrIndex)¶
-
getElementAsBool
(name)¶ - Parameters
- Returns
This element’s sub-element with
name
as a boolean- Return type
- Raises
Exception – If
name
is neither aName
nor a string, or if thisElement
is neither a sequence nor a choice, or in case it has no sub-element with the specifiedname
, or in case the element’s value can’t be returned as a boolean.
-
getElementAsDatetime
(name)¶ - Parameters
- Returns
This element’s sub-element with
name
as one of the datetime types- Return type
- Raises
Exception – If
name
is neither aName
nor a string, or if thisElement
is neither a sequence nor a choice, or in case it has no sub-element with the specifiedname
, or in case the element’s value can’t be returned as a datetime.
-
getElementAsFloat
(name)¶ - Parameters
- Returns
This element’s sub-element with
name
as a float- Return type
- Raises
Exception – If
name
is neither aName
nor a string, or if thisElement
is neither a sequence nor a choice, or in case it has no sub-element with the specifiedname
, or in case the element’s value can’t be returned as a float.
-
getElementAsInteger
(name)¶ - Parameters
- Returns
This element’s sub-element with
name
as an integer- Return type
- Raises
Exception – If
name
is neither aName
nor a string, or if thisElement
is neither a sequence nor a choice, or in case it has no sub-element with the specifiedname
, or in case the element’s value can’t be returned as an integer.
-
getElementAsName
(name)¶ - Parameters
- Returns
This element’s sub-element with
name
as aName
- Return type
- Raises
Exception – If
name
is neither aName
nor a string, or if thisElement
is neither a sequence nor a choice, or in case it has no sub-element with the specifiedname
, or in case the element’s value can’t be returned as aName
.
-
getElementAsString
(name)¶ - Parameters
- Returns
This element’s sub-element with
name
as a string- Return type
- Raises
Exception – If
name
is neither aName
nor a string, or if thisElement
is neither a sequence nor a choice, or in case it has no sub-element with the specifiedname
, or in case the element’s value can’t be returned as a string.
-
getElementValue
(name)¶
-
getValue
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
defined by this element’s datatype.- Raises
InvalidConversionException – If the data type of this
Element
is either a sequence or a choice.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsBool
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as a boolean.- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to a boolean.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsDatetime
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as one of the datetime types.- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to a datetime.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsElement
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as a Element.- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to anElement
.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsFloat
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as a float.- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to an float.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsInteger
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as a integer- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to an integer.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsName
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as a Name.- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to aName
.IndexOutOfRangeException – If
index >= numValues()
.
-
getValueAsString
(index=0)¶ - Parameters
index (int) – Index of the value in the element
- Returns
index
th entry in theElement
as a string.- Return type
- Raises
InvalidConversionException – If the data type of this
Element
cannot be converted to a string.IndexOutOfRangeException – If
index >= numValues()
.
-
hasElement
(name, excludeNullElements=False)¶
-
isArray
()¶ - Returns
True
if this element is an array.- Return type
This element is an array if
elementDefinition().maxValues()>1
or ifelementDefinition().maxValues()==UNBOUNDED
.
-
isComplexType
()¶ - Returns
True
ifdatatype()==DataType.SEQUENCE
ordatatype()==DataType.CHOICE
andFalse
otherwise.- Return type
-
isNullValue
(position=0)¶
-
name
()¶ - Returns
If this
Element
is part of a sequence or choiceElement
, then return theName
of thisElement
within the sequence or choiceElement
that owns it. If thisElement
is not part of a sequenceElement
(that is it is an entireRequest
orMessage
) then return theName
of theRequest
orMessage
.- Return type
-
numElements
()¶ - Returns
Number of elements in this element.
- Return type
The number of elements is
0
ifisComplexType()
returnsFalse
, and no greater than1
if theDataType
isCHOICE
; if theDataType
isSEQUENCE
this may return any number (including0
).
-
numValues
()¶ - Returns
Number of values contained by this element.
- Return type
The number of values is
0
ifisNull()
returnsTrue
, and no greater than1
ifisComplexType()
returnsTrue
. The value returned will always be in the range defined byelementDefinition().minValues()
andelementDefinition().maxValues()
.
-
setElement
(name, value)¶ Set this Element’s sub-element with ‘name’ to the specified ‘value’.
- Parameters
- Raises
Exception – If
name
is neither aName
nor a string, or if this element has no sub-element with the specifiedname
, or if theElement
identified by the specifiedname
cannot be initialized from the type of the specifiedvalue
.
This method can process the following types of
value
without conversion:boolean
integers
float
string
datetypes (
datetime.time
,datetime.date
ordatetime.datetime
)
Any other
value
will be converted to a string withstr
function and then processed in the same way as stringvalue
.
-
setValue
(value, index=0)¶ Set the specified
index
th entry in thisElement
to thevalue
.- Parameters
index (int) – Index of the sub-element
value – Value to set the sub-element to
- Raises
Exception – If this
Element
’s datatype can’t be initialized with the type of the specifiedvalue
, or ifindex >= numValues()
.
This method can process the following types of
value
without conversion:boolean
integers
float
string
datetypes (
datetime.time
,datetime.date
ordatetime.datetime
)
Any other
value
will be converted to a string withstr
function and then processed in the same way as stringvalue
.
-
toString
(level=0, spacesPerLevel=4)¶ Format this
Element
to the string at the specified indentation level.- Parameters
- Returns
This element formatted as a string
- Return type
If
level
is negative, suppress indentation of the first line. IfspacesPerLevel
is negative, format the entire output on one line, suppressing all but the initial indentation (as governed bylevel
).
-
values
()¶ - Returns
Iterator over values contained in this
Element
.
If
isComplexType()
returnsTrue
for thisElement
, the empty iterator is returned.