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The History node creates new fields containing data from fields in previous records. History
nodes are most often used for sequential data, such as time series data. Before using a History
node, you may want to sort the data using a Sort node.
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Example
node = stream.create("history", "My node")
node.setPropertyValue("fields", ["Drug"])
node.setPropertyValue("offset", 1)
node.setPropertyValue("span", 3)
node.setPropertyValue("unavailable", "Discard")
node.setPropertyValue("fill_with", "undef")
Table 1. historynode properties
historynode properties |
Data type |
Property description |
fields
|
list |
Fields for which you want a history. |
offset
|
number
|
Specifies the latest record (prior to the current record) from which you want to extract
historical field values. |
span
|
number
|
Specifies the number of prior records from which you want to extract values. |
unavailable
|
Discard
Leave
Fill
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For handling records that have no history values, usually referring to the first several
records (at the top of the dataset) for which there are no previous records to use as a history.
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fill_with
|
String
Number
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Specifies a value or string to be used for records where no history value is available.
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