TERR_TimeSpan

In the Spotfire Custom Expressions dialog box, you can select the pre-defined expression TERR_TimeSpan from the Function list. This expression function invokes the TERR engine to return a vector or a single column data frame of the data type difftime , which is converted to a Spotfire column of the corresponding Spotfire data type TimeSpan.

The expression function has at least two arguments.
Argument	Argument description
A TERR script.	The TERR script contains the following. A number of variables using the naming convention that Spotfire requires: `input1` to `inputN`, where `inputN` is the highest number of the specified inputs, numbered sequentally. A TERR assignment operator (`<-`) that assigns the results of the TERR evaluation to an object named `output` (also using the naming convention that Spotfire requires).
Spotfire column names.	Passed as additional arguments, these are the data column names that `input1` to `inputN` represent. All columns must be the same length.

The output type is returned from TERR and converted by Spotfire.
Returned by TERR	Converted in Spotfire
A vector or a single column data frame of data type `difftime`.	A column with the same number of rows as the input, and of the data type TimeSpan.

TERR_TimeSpan example

In this example, in Spotfire, take thirty observations with a start time and an end time. You can find the sample data set in Observation data set for Spotfire examples.

Tip: You can copy (CTRL+C) the contents of the sample data table and paste it (CTRL+V) into the Spotfire user interface.

Calculate the observation time for each entry.

TERR_TimeSpan("output <- difftime(input1, input2)",[End time],[Start time])

In the example, we named the resulting column Elapsed time and added the column to a table visualization. The resulting table in Spotfire shows the following.

Important: Spotfire autocorrects the function case or name to that of built-in Spotfire function names. (For example, TERR contains the function max, and Spotfire contains the function Max. ) You must overwrite this autocorrection manually to ensure that you use the TERR function case and name in your expression function.

See Embedding the Contents of a Script in an Expression Function for a detailed procedure for creating an expression function.