caption: splitregexp
created: 20190613154722705
modified: 20190613154924724
op-input: a [[selection of titles|Title Selection]]
op-output: the input titles split into separate items according to the specified regular expression <<.place R>>
op-parameter: The regular expression at which to split each title
op-parameter-name: R
op-purpose: returns each item in the list split into separate strings according to the specified regular expression <<.place R>>
op-suffix: flags: ''m'' for multiline mode, ''i'' for case-insensitive mode
tags: [[Filter Operators]]
title: splitregexp Operator
type: text/vnd.tiddlywiki

<<.from-version "5.1.20">>

Note that in some circumstances the <<.op splitregexp>> operator will include blank items in the list of results. For example, 

```
[[the band thethe are the best the]splitregexp[the]]
```

The following results are returned:

```
["", " band ", "", " are ", " best ", ""]
```

Where it might be expected that the results would be:

```
[" band ", " are ", " best "]
```

The blank items mark the boundaries between matches. If they are not required they can be removed with the ''blank'' category of the [[is Operator]]: `[[the band thethe are the best the]splitregexp[the]!is[blank]]`.

The reason that the blank items can be useful is that they allow search and replace operations to be constructed from a combination of the [[split Operator]] or [[splitregexp Operator]] and the [[join Operator]]. For example:

<<.operator-example 1 "[[nobody, really; wants; to see -- all this \punctuation]splitregexp[,|;|-|\\]join[...]]">>

Syntax errors in the regular expression will cause the filter to return an error message. For example:

<<.operator-example 2 "[[the cat sat on the mat]splitregexp[\]]">>

<<.operator-examples "splitregexp">>
