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      Function Overview
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      Contents

      Function Overview

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      Article summary

      Function fields - also known as "BakedFields" - are inbuilt DataJet functions that can be applied to existing data fields in order rapidly create new fields.  Along with Expressions, DataSetFields and User-Defined Fields they play a key role in the transformation of data.

      See Baked Fields for an overview of Baked Fields

      Find Function

      Accessed via Engineering | Functions | Find Function

      The Find Function dialog allows functions to be searched for via keywords: 

      It is also possible to filter results by function group.

      Double-click a function to bring up the function selector.


      Function Selector

      Accessed via Engineering | Functions | Selector

      The Function Selector Dialog first requires either a function group, or a general function to be selected.

      (Click the search icon to bring up the function search dialog)

      Select a function/group and sub function

      • Enter table that that field is to be created on
      • Apply a filter of records to be included when building the new field (optional - if not provide, all records in the source table will be included)
      • Enter parameters 
      • Specify a name for the new field
      • Click Build


      Parameters

      Parameters can be of two types:

      • fields
      • fixed values

      fixed values must be prefixed by the pound sign (#):

      Methods for Adding Parameters
      Parameters can be added to the function dialog in the following ways:
      • Drag and drop from the Database Explorer
      • Type the parameter name or value
      • Select the required field in the Database Explorer, press  CTRL C to copy the field name to clipboard, and then do CTRL V to paste into the fnuction dialog
      • Select the required field from the drop down 

      Do Not Ordinalize

      If available and checked, this will force the field to be created as a continuous field.  Note this added the "flags": "NOORD" key to the executed JSON:

      {
  "method": "BuildBakedField",
  "project": "Election5",
  "targetTable": "PA_All",
  "overwrite": true,
  "name": "NoOrd",
  "function": "string",
  "p1": "CONCAT(A,B,C,D,E,F)",
  "p2": "geo_id",
  "p3": "#_",
  "p4": "locality_fips",
  "flags": "NOORD"
}

      Properties

      To see the JSON that was used to create a BakedField, select the field in the Database Explorer, right-click and choose Properties:


      Existing Fields

      Using an existing field as a template
      To create a copy of an existing field, select it in the Project Explorer, right-click and choose Edit - the function dialog will be opened with the parameters for the existing field. Change the function name to be the name of the new field, click build, and a copy of the field will be created.
      Existing Fields
      If a field of the specified name already exists, an overwrite prompt will be displayed.   Choosing to overwrite will permanently change the existing field content.    If a field is written over by mistake, access the Project History to retrieve the earlier version.


      Functions

      The following function groups are available on the function menu:

      • General - general functions, including key creation, discrete value processing, access to indexes, joinlayer functions and quantiles.
      • DateTimeTransform - transformations involving hours, minutes and seconds
      • DateTransform - transformations involving years, months and days
      • DMath - transformations producing decimal fields
      • LMath - transformations that produce integer fields
      • FLogic - logical functions that evaluate conditions and produce flag fields
      • Geo - geographical functions, including distance calculations
      • Statistical - distributions and transformation that support data modelling and cleaning
      • String - transformations of string data
      • UserAgent - extractions of web data


      The function menu can be accessed via:



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