caption: getvariable
created: 20190330100101453
modified: 20240219183835439
op-input: a selection of variable names
op-output: the values of each of the variables named in the input titles (or blank if the variable is not defined)
op-parameter: <<.from-version "5.3.4">> defaults to: "text". optional: "value". Content type <<.param T>> of the varible content that should be returned
op-purpose: select all values of variables named in the input titles
tags: [[Filter Operators]] [[Special Operators]]
title: getvariable Operator
type: text/vnd.tiddlywiki

<<.from-version "5.1.20">> The usual way to retrieve a variable value within a filter is with the angle brackets notation. For example, `[<currentTiddler>]` will retrieve the value of the variable called `currentTiddler`. 

The `getvariable` filter operator provides an alternative way to retrieve a variable. For example, `[[currentTiddler]getvariable[]]` is another way to retrieve the value of the variable `currentTiddler`.

The advantage of `getvariable` is that it makes it possible to work with variables whose name is computed, and not known in advance. For example, `[<myvariable>getvariable[]]` gets the value of the variable whose name is given in the variable `myvariable`.

''Content Type:'' <<.from-version "5.3.4">>

The Prameter <<.param T>> by default is "text". Variables, that are defined as eg: `\function`s have two useful content types: 

* ''text'' ... contains the wikified text of the filter expression
* ''value'' ... contains the definition string

For any other variable type "text" and "value" are the same thing. 

<<.operator-examples "getvariable">>