caption: getindex
created: 20150203140000000
modified: 20230309163838670
op-input: a [[selection of titles|Title Selection]]
op-output: the values of property <<.place P>> in each of the input titles
op-parameter: the name of a [[property|DataTiddlers]]
op-parameter-name: P
op-purpose: select all values of a data property in the input titles
tags: [[Filter Operators]] [[Field Operators]]
title: getindex Operator

Each input title is processed in turn, and is ignored if it does not denote a [[data tiddler|DataTiddlers]]. If the corresponding tiddler contains property <<.place P>>, and the value of this property is not empty, then its value is appended to the output.

<<.tip "Unlike most other [[Filter Operators]], the [[selection|Title Selection]] output by <<.op getindex>> can contain duplicates. To avoid duplicates, use `getindex[P]unique[]`.">>

<<.operator-examples "getindex">>
