g_interp(G;S;O;X;N)

Returns interpolations for N/A values in a given group.

Function type

Vector only

Syntax

g_interp(G;S;O;X;N)

Input

Argument Type Description
G any A space- or comma-separated list of column names

Rows are in the same group if their values for all of the columns listed in G are the same.

If G is omitted, all rows are considered to be in the same group.

If any of the columns listed in G contain N/A, the N/A value is considered a valid grouping value.
S integer The name of a column in which every row evaluates to a 1 or 0, which determines whether or not that row is selected to be included in the calculation

If S is omitted, all rows will be considered by the function (subject to any prior row selections).

If any of the values in S are neither 1 nor 0, an error is returned.
O integer The name of a column that determines the row order within a particular group and the spacing of values for the purpose of interpolation

If O is omitted, the order is the current display order of the table, and values are treated as evenly spaced.

If any of the values in O are N/A, an error is returned.
X integer or decimal A column name
N integer A value that indicates how N/A values are interpolated or extrapolated based on nearby values, using N-order interpolation

Valid values are:

  • 0 - previous value
  • 1 - linear interpolation
  • 2 - quadratic interpolation
  • 3 - cubic spline interpolation
Note: If omitted, N defaults to 1.

Return Value

For every row in each group defined by G and ordered by O (and for those rows where S=1, if specified), g_interp returns the decimal value of the current row in X, if it is not N/A. Otherwise, N/A values in X are interpolated or extrapolated based on nearby values, using N-order interpolation (i.e., N=0: previous value; N=1: linear interpolation; N=2: quadratic; N=3: cubic splines).

Sample Usage

<base table="pub.doc.samples.ref.func.g_func_time_series_sample_usage"/>
<willbe name="g_interp_1" value="g_interp(state;include;order;value;1)"/>
<willbe name="g_interp_2" value="g_interp(state city;include;order;value;2)"/>

Additional Information

  • The t_ version of this function defaults the G argument and omits the S argument. The default for G is set at table load time based on the organization of the table.