TiddlyWiki5/editions/tw5.com/tiddlers/filters/compare Operator.tid

created: 20200412181551706
modified: 20200412181551706
tags: [[Filter Operators]] [[Mathematics Operators]] [[String Operators]] [[Negatable Operators]]
title: compare Operator
type: text/vnd.tiddlywiki
caption: compare
op-purpose: filter the input by comparing each item against the parameter
op-input: a [[selection of titles|Title Selection]]
op-suffix: the <<.op compare>> operator uses a rich suffix, see below for details
op-parameter: the value to compare
op-output: those input titles matching the specified comparison
op-neg-output: those input titles <<.em not>> matching the specified comparison

<<.from-version "5.1.22">>The <<.op compare>> filter allows numerical, string and date comparisons to be performed.

The <<.op compare>> operator uses an extended syntax to specify all the options:

```
[compare:<type>:<mode>[<parameter>]]
```

The ''type'' can be:

* "number" - invalid numbers are interpreted as zero
* "integer" - invalid integers are interpreted as zero
* "string"
* "date" - invalid dates are interpreted as 1st January 1970
* "version" - invalid versions are interpreted as "v0.0.0"

The ''mode'' can be:

* "eq" - equal to
* "ne" - not equal to
* "gteq" - greater than or equal to
* "gt" - greater than
* "lteq" - less than or equal to
* "lt" - less than

The operator compares each item in the selection against the value of the parameter, retaining only those items that pass the specified condition.

For example:

```
[[2]compare:number:eq[3]] returns nothing
[[2]compare:number:lt[3]] returns "2"
[[2]compare:number:eq[2]] returns "2"
```

Note that several of the variants of the <<.op compare>> operator are synonyms for existing operators, and are provided in the interests of consistency. For example, `compare:string:eq[x]` is a synonym for `match[x]`.

<<.operator-examples "compare">>