historynode properties

Last updated: Jan 18, 2024

History node icon 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.

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`	For handling records that have no history values, usually referring to the first several records (at the beginning of the dataset) for which there are no previous records to use as a history.
`fill_with`	`String` `Number`	Specifies a value or string to be used for records where no history value is available.