Interpolate
Fills gaps in a column of numbers by estimating the missing values from their neighbors. Use it when a data feed skipped a few periods, or a monthly series has holes that would break running totals and charts. Values that are already present are never changed.
Inputs
| Input | Accepts | Required |
|---|---|---|
Series | Series (a list of numbers) | Yes |
Outputs
| Output | Produces |
|---|---|
Result | Series (a list of numbers) |
Settings
Typed in on the node or set by the assistant, not wired.
| Setting | Default | Notes |
|---|---|---|
Method | Linear | Linear (default) draws a straight line between the known values on either side of a gap. Nearest copies the closest known value instead. |
Example
A Headcount_Cost column is missing two months: 410,000, 415,000, (blank), (blank), 430,000, 436,000. With the Linear method, the two gaps are bridged in even steps: 420,000 and 425,000. The filled series now charts as a continuous line and downstream running totals stay meaningful instead of dropping to zero mid-year.
Tips
Linear suits values that trend, like costs or revenue. Nearest suits values that hold steady between resets, like a contracted rate. Gaps at the very start or end of the series have only one neighbor, so the nearest known value is carried across them flat. Interpolate estimates between known points; it does not project a trend forward. For that, use ExtendForecast or ForecastSeries.