Search Pattern Cookbook

The Search function is very powerful. Searches using a Regular Expression play an important part of tapping Foswiki's full potential. Unfortunately Regular Expressions can be incredibly obscure to the uninitiated.

Most people not familiar (enough) with Regular Expressions mostly cut and paste (and maybe tweak) from existing examples. This page intends to collect lots of examples together.

Pattern 1: Extract values from a table

Problem definition

Suppose there is a topic with a table defining entries in a data form. I.e. they define select menu items in a form definition. They are then formatted like:

| *Name*  | *Type* | *Tooltip message* |
| option1 | option |                   |
| option2 | option |                   |
| option3 | option |                   |

How to extract the 'name' values, i.e. 'option1', 'option2' and 'option3' and put them in a HTML form select input?

Solution 1

The following search pattern can be employed:

<form>
    <select>
        %SEARCH{
            "^\|[^\|]*\| *option *\|"
            topic="%TOPIC%"
            type="regex"
            multiple="on"
            nonoise="on"
            format="<option>$pattern(^\| *(.*?) *\|.*)</option>"
        }%
    </select>
</form>

which is, in effect:

Solution 2

If your table has this format:
| *Country*      |
|                |
| Afghanistan    |
| Aland Islands  |
| Albania        |
| Algeria        |
| American Samoa |
| Andorra        |

You need to skip the header row. Use this search:
<select>
    %SEARCH{
        "^\|[^\*\|]*\|"
        topic="CountryList"
        type="regex"
        multiple="on"
        nonoise="on"
        format="<option>$pattern(^\| *(.*?) *\|.*)</option>"
    }%
</select>

Which renders as:

Solution 3

If you want to grab the complete row for each occurrence of a string in a table, for instance the word "Marketing":
| a | b | c | d | e |
| Marketing | b | c | d | e|
| a | b | c | d | e |
| a | marketing | c | d | e | 
| a | b | c | d | marketing | 

use this query:
%SEARCH{
    "^\|.*?Marketing.*"
    type="regex"
    topic="%TOPIC%"
    multiple="on"
    nonoise="on"
    format="| $pattern(^\| *(.*?) *|.*)"
}%

Which renders as:
Marketing b c d e
a marketing c d e
a b c d marketing

Pattern 2: List generated from form classification

Problem

Imagine a form-based topic classification, i.e. every page has a form with several fields. How to:
  1. create a search to display all topics where one form field is set to a certain value
  2. create a search to filter the list above based on the values of a second form field

Test case

In practice:
Image a form with two fields:
  • TopicClassification = One, Two or Three
  • TopicStatus = Test or Final

We will:
  1. List all topics where the TopicClassification field is set to 'Two'
  2. Enable the user to filter this list based on the values of TopicStatus

Solution

%SEARCH{
    "TopicClassification='%URLPARAM{type}%'"
    type="query"
    nonoise="on"
    sort="topic"
    format="   * $topic - <font face='arial,helvetica' size='1'> 
    _last modified by_ $wikiusername _on_ $date </font> %BR% &nbsp;&nbsp;&nbsp; 
    <font face='arial,helvetica' size='1'> $formfield(TopicStatus) </font>" 
}%

The filtering select dialogue is created as in Pattern 1:

%STARTSIDEBAR%
*Filter:* %BR%
<form name="selectType" action="%SCRIPTURLPATH{"view"}%/%WEB%/" >
    <select name="type" size="1" onchange="document.location=this.value;"> 
        %SEARCH{
            "^\|[^\|]*\| *option *\|"
            topic="TopicClassification"
            type="regex" 
            nonoise="on"
            format="<option value='%BASETOPIC%?type=$pattern(^\| *(.*?) *\|.*)'>
                $pattern(^\| *(.*?) *\|.*)</option>"
        }% 
        <option value='%BASETOPIC%'>All pages</option>
    </select>
</form>
%STOPSIDEBAR% 

This will create similar functionality as Foswiki:Extensions.TopicClassificationAddOn

Pattern 3: Extract the parent of a given topic

Problem

How to get to the parent of the current topic to display on the page?

Solution 1: Using QUERY

Use the QUERY macro:

%QUERY{ "parent.name" }%

Test case

Formatted Search

Pattern 4: Show all Children of a given topic

Problem

How to get to the list of all children of the current topic to display on the page?

Solution

The parent information is stored in the topic meta data. Do a SEARCH to find all topic parent meta data pointing to the current topic:

Children:
%SEARCH{
    "parent.name='%TOPIC%'"
    type="query"
    nonoise="on"
    format="[[$topic]]"
    separator=", "
}%

Note: Replace %TOPIC% with %BASETOPIC% if you put this SEARCH into the skin or a sidebar.

See also Hierarchical Navigation for an elaborate example.

Pattern 5: Search and display the home topics of public webs in a list

Problem

How to find and display public webs in a drop down list box.

Solution

<form>
    <select name="topic">
        <option value="%TOPIC%">Select...</option>
            %SEARCH{
                "%HOMETOPIC%"
                scope="topic"
                web="all"
                topic="%HOMETOPIC%"
                format="<option value='$web.$topic'>$web</option>"
                separator=" "
            }%
    </select>
    <input type="submit" class="foswikiSubmit" value="Go" />
</form>

Test case

Public webs can be found with the %WEBLIST% macro.

Pattern 6: Create a select box with values from a bullet list

Problem

We have a topic with a bullet list with category names. In another topic we want to offer these values in a select box dropdown.

For example, CategoryList has:
  • Clients
  • People
  • Rooms
  • Buildings

Solution

The following search pattern can be employed:

<select name="type">
    <option>Select category...</option>
    %SEARCH{
        "   *\s*.*?"
        topic="CategoryList"
        type="regex"
        multiple="on"
        casesensitive="on"
        nonoise="on"
        format="<option>$pattern(.*   \*\s*([^\n]*).*)</option>"
    }%
</select>

To render the bullet list as a comma-separated list, use the separator parameter:
%SEARCH{
    "   *\s*.*?"
    topic="CategoryList"
    type="regex"
    multiple="on"
    casesensitive="on"
    nonoise="on"
    separator=","
    format="$pattern(.*   \*\s*([^\n]*).*)"
}%

Pattern 7: Search all topics that have been moved

Problem

How would I go about listing all moved topics ?

Solution

Search for the 'moved' meta data. Type this:

Moved topics: %SEARCH{
    "moved.from=~'\w+'"
    web="all"
    type="query"
    separator=", "
    format="$web.$topic"
    nonoise="on"
}%

Test case

Moved topics: Climat Conseil General 79 Group, Climat Grand Poitiers Group, Stagiaires Group, Sylvie Sap, La Science Se Livre 2006, La Science Se Livre 2007, Stagiaires Group, Nat Skin Test, Txt 2 Tags Sample, Appendix Cascading Style Sheets, FAQAn Application With Wiki Form, FAQDelete Or Rename ATopic, FAQDelete Or Rename An Attachment, FAQDownload Sources, FAQEdit Does Not Increase The Revision, FAQGnu General Public License, FAQSearch Does Not Work, FAQSimultaneous Edits, FAQWhat Is Wiki Wiki, Var METASEARCH, Aide En Ligne, Album Photos, Bien Utiliser Twiki, Communique De Presse, Communique De Presse Infos, Document Officiel, Documentation En Francais, Etudes Et Documents, Fiche Standard, Gestion Des Espaces, Manuel Agenda En Ligne, Mot Wiki, Page Projet, Pilotage Agenda, Procedure Operationnelle, Recherche Par Type, Ressource Emf, Slide Show S5 Template, Suivis De Travaux, TWiki En Vingt Minutes, TWiki Raccourcis, Telem En Vingt Minutes, Web Notify, Web Topic Creator, Wiki Raccourcis, Wok Taxon, Wok Taxon Specimen

Pattern 8: Extract level-1 headings

How do I go about extracting the first occurance of a level-1 heading?

Solution

Use the $pattern() token. Type this:

%SEARCH{
    "^---[+][^+][^\r\n]+[\r\n]"
    type="regex"
    nonoise="on"
    header="Headings:"
    limit="5"
    format="   * [[$topic][$pattern([\r\n\-+!]+([^\r\n]*?)[\r\n].*)]]"
    footer="Found $ntopics topics with level-1 headings"
}%

Test case

Headings: Found 5 topics with level-1 headings


Related Topics: User Documentation Category, Search Help, Macros, Formatted Search, Regular Expression
Topic revision: r1 - 23 Aug 2010, ProjectContributor
 
This site is powered by FoswikiCopyright © by the contributing authors. All material on this site is the property of the contributing authors.
Ideas, requests, problems regarding Telem? Send feedback