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lookup Operator

16th January 2021 at 8:13am
purposeapplies a prefix to each input title to yield the title of a tiddler from which the final value is retrieved. With a single parameter, the default field is "text" and the default index is "0". If a second parameter is provided, that becomes the target field or index.
inputa selection of titles
suffixD, I=the default value to be used for missing lookups. This operator can now accept a second suffix of :index, see below for details
parameterP, T=prefix applied to input titles to yield title of lookup tiddler from which value is retrieved. Now accepts 1 or 2 parameters, see below for details
outputthe lookup values corresponding to each lookup tiddler

Learn more about how to use Filters

Introduced in v5.1.15

The action of this operator is as follows with 1 parameter:

  • Apply the specified prefix to each input tiddler title, yielding a new list of tiddler titles
  • Transclude the value of the text field each of those tiddlers
    • Substitute the default value for missing or empty values
  • Return the list of values
Introduced in v5.2.2

The use of the :index second suffix changes the default lookup location from field: text to index: 0. This is used if no 2nd parameter is provided.

The action of this operator is as follows with 2 parameters:

If there are two parameters provided, use the second parameter as the target field or index.

Note
If there is only one parameter given, the filter checks for a second suffix equal to "index". If this suffix is found, the default target index is "0". In all other cases, the default target field is "text".

Then:

  • Apply the specified prefix to each input tiddler title, yielding a new list of tiddler titles
  • Transclude the value of the target field or index
    • Substitute the default value for missing or empty values
  • Return the list of values

Examples