# PreFilterTaskN

The name of an Eduction pre-filtering task to run. This parameter specifies the name of a section in the Eduction configuration file that contains the parameters required to run the task. Replace the value `N` with the number of the task, starting from zero (`PreFilterTask0`, `PreFilterTask1`, and so on)

Pre-filtering tasks use a regular expression to perform an initial check to find strings that might match an entity in your input text. It then restricts Eduction matching to windows of several characters around these potential matches. This process can improve performance for some grammars, by restricting the amount of the input text that Eduction checks in detail for matches.

In the pre-filter configuration sections, you set Regex to a regular expression that finds potential matches. You use WindowCharsAfterMatch and WindowCharsBeforeMatch to specify the size of the matching window to use.

Eduction runs all your configured pre-filtering tasks for all input text, so ensure that your pre-filter task applies to all your configured grammars and entities. Use a different configuration for any entities that you do not want to pre-filter.

When you configure multiple pre-filtering tasks, Eduction runs each of them on your full input text. It then merges any windows that overlap from different tasks, and uses all the resulting windows as input text for the full matching process.

Type: | String
Default: | None
Required: | No
Configuration Section: |
Example: | `[Eduction] PreFilterTask0=AddressPreFilter [AddressPreFilter] Regex=\d{1,7} WindowCharsAfterMatch=100 WindowCharsBeforeMatch=100`
See Also: |

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