Help:Switch parser function - Revision history

Cedar101: /* General format */ lang="wikitext", {{param}}

2025-02-06T23:58:21Z

General format: lang="wikitext", {{param}}

← Previous revision		Revision as of 23:58, 6 February 2025
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	</syntaxhighlight>		</syntaxhighlight>

	That one-line {{mono\|#switch}} would read the value of {{~~mono~~\|~~<nowiki>{{{~~x~~}}}</nowiki>~~}}. For a value of 1 it would return "one". For a value of 2 it would return "two". For the values 3, 4 or 5 it would return "range 3–5". For any other value, or a null value, it would return "other".		That one-line {{mono\|#switch}} would read the value of {{param\|x}}. For a value of 1 it would return "one". For a value of 2 it would return "two". For the values 3, 4 or 5 it would return "range 3–5". For any other value, or a null value, it would return "other".

	However, in many cases, the {{mono\|#switch}} function is a multi-line form, with each branch on a different line, as follows:		However, in many cases, the {{mono\|#switch}} function is a multi-line form, with each branch on a different line, as follows:

	<syntaxhighlight lang="~~html~~">		<syntaxhighlight lang="wikitext">
	{{#switch: {{{x}}}		{{#switch: {{{x}}}
	\| 1 = one		\| 1 = one

.hecko: /* Using switches as if-elseif-elseif */pedantic correction

2024-12-09T07:56:17Z

Using switches as if-elseif-elseif: pedantic correction

← Previous revision		Revision as of 07:56, 9 December 2024
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	}}		}}
	</syntaxhighlight>		</syntaxhighlight>
	When testing x2 and y2, if either of them is ~~zero~~ ~~(none)~~, then the #switch ends with a warning message, rather than calculating the [[weighted average]] of the two amounts x, y, with x2 and y2. Each branch acts as a pre-condition, so the whole #switch structure performs as equivalent to ''if-elseif-elseif-elseif-else'', even though an #if-function structure cannot have an "elseif" clause. Note the 2 types of data compared:		When testing x2 and y2, if either of them is empty or zero, then the #switch ends with a warning message, rather than calculating the [[weighted average]] of the two amounts x, y, with x2 and y2. Each branch acts as a pre-condition, so the whole #switch structure performs as equivalent to ''if-elseif-elseif-elseif-else'', even though an #if-function structure cannot have an "elseif" clause. Note the 2 types of data compared:

	; Alphabetic data		; Alphabetic data

178.197.211.212: Removed wrong statement. Comparison is made numerically if both strings being tested are numeric. See mediawiki help page

2024-10-02T17:38:15Z

Removed wrong statement. Comparison is made numerically if both strings being tested are numeric. See mediawiki help page

← Previous revision		Revision as of 17:38, 2 October 2024
Line 3:		Line 3:
	The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].		The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].

	Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not require the "Template:" prefix. For example, the following are equivalent template calls: {{tlc\|Template:Foobar}} and {{tlc\|Foobar}}.</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="wikitext" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.		Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not require the "Template:" prefix. For example, the following are equivalent template calls: {{tlc\|Template:Foobar}} and {{tlc\|Foobar}}.</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure.

	A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.		A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.

Hemiauchenia: Undid revision 1186268065 by 119.252.112.234 (talk)

2023-11-22T02:22:53Z

Undid revision 1186268065 by 119.252.112.234 (talk)

← Previous revision		Revision as of 02:22, 22 November 2023
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	== General format ==		== General format ==
	The {{mono\|#switch}} function can be a one-line form:		The {{mono\|#switch}} function can be a one-line form:

			<syntaxhighlight lang="wikitext">
			{{#switch: {{{x}}} \|1=one \|2=two \|3\|4\|5=range 3–5 \|other}}
			</syntaxhighlight>

	That one-line {{mono\|#switch}} would read the value of {{mono\|<nowiki>{{{x}}}</nowiki>}}. For a value of 1 it would return "one". For a value of 2 it would return "two". For the values 3, 4 or 5 it would return "range 3–5". For any other value, or a null value, it would return "other".		That one-line {{mono\|#switch}} would read the value of {{mono\|<nowiki>{{{x}}}</nowiki>}}. For a value of 1 it would return "one". For a value of 2 it would return "two". For the values 3, 4 or 5 it would return "range 3–5". For any other value, or a null value, it would return "other".

	However, in many cases, the {{mono\|#switch}} function is a multi-line form, with each branch on a different line, as follows:		However, in many cases, the {{mono\|#switch}} function is a multi-line form, with each branch on a different line, as follows:

			<syntaxhighlight lang="html">
			{{#switch: {{{x}}}
			\| 1 = one
			\| 2 = two
			\| #default = other
			\| 3\|4\|5 = any of 3–5
			\| {{#expr: 2*3}} = six
			\| {{#expr: 2*3+1}} = {{lc:SEVEN}} <!--lowercase-->
			}}
			</syntaxhighlight>

	This illustrates an alternative method of specifying the default case, which can appear first, last, or anywhere in between.		This illustrates an alternative method of specifying the default case, which can appear first, last, or anywhere in between.

119.252.112.234 at 00:46, 22 November 2023

2023-11-22T00:46:43Z

← Previous revision		Revision as of 00:46, 22 November 2023
Line 9:		Line 9:
	== General format ==		== General format ==
	The {{mono\|#switch}} function can be a one-line form:		The {{mono\|#switch}} function can be a one-line form:

	<syntaxhighlight lang="wikitext">
	{{#switch: {{{x}}} \|1=one \|2=two \|3\|4\|5=range 3–5 \|other}}
	</syntaxhighlight>

	That one-line {{mono\|#switch}} would read the value of {{mono\|<nowiki>{{{x}}}</nowiki>}}. For a value of 1 it would return "one". For a value of 2 it would return "two". For the values 3, 4 or 5 it would return "range 3–5". For any other value, or a null value, it would return "other".		That one-line {{mono\|#switch}} would read the value of {{mono\|<nowiki>{{{x}}}</nowiki>}}. For a value of 1 it would return "one". For a value of 2 it would return "two". For the values 3, 4 or 5 it would return "range 3–5". For any other value, or a null value, it would return "other".

	However, in many cases, the {{mono\|#switch}} function is a multi-line form, with each branch on a different line, as follows:		However, in many cases, the {{mono\|#switch}} function is a multi-line form, with each branch on a different line, as follows:

	<syntaxhighlight lang="html">
	{{#switch: {{{x}}}
	\| 1 = one
	\| 2 = two
	\| #default = other
	\| 3\|4\|5 = any of 3–5
	\| {{#expr: 2*3}} = six
	\| {{#expr: 2*3+1}} = {{lc:SEVEN}} <!--lowercase-->
	}}
	</syntaxhighlight>

	This illustrates an alternative method of specifying the default case, which can appear first, last, or anywhere in between.		This illustrates an alternative method of specifying the default case, which can appear first, last, or anywhere in between.

Fallbackintoreality: moves notes from below the navbox to above it

2023-08-14T12:51:15Z

moves notes from below the navbox to above it

← Previous revision		Revision as of 12:51, 14 August 2023
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	The upper branches of a #switch execute faster, and the bottom branches must wait for comparisons of all higher branches. Hence, the top branch should be the most-used case, unless pre-screening of data is done in the early branches.		The upper branches of a #switch execute faster, and the bottom branches must wait for comparisons of all higher branches. Hence, the top branch should be the most-used case, unless pre-screening of data is done in the early branches.

			== Notes ==
			<references />
	== See also ==		== See also ==
	* [[Wikipedia:Parser function]]		* [[Wikipedia:Parser function]]

Daask: Simplify and clarify wording about template calls

2023-08-09T11:22:08Z

Simplify and clarify wording about template calls

← Previous revision		Revision as of 11:22, 9 August 2023
Line 3:		Line 3:
	The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].		The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].

	Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not ~~include~~ the "Template:" prefix. {{tlc\|Template:Foobar}} ~~also~~ ~~works, but "Template:" is not necessary. The result is "~~{{tlc\|Foobar}}".</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="wikitext" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.		Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not require the "Template:" prefix. For example, the following are equivalent template calls: {{tlc\|Template:Foobar}} and {{tlc\|Foobar}}.</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="wikitext" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.

	A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.		A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.

Daask: Tidy see also

2023-08-09T11:19:24Z

Tidy see also

← Previous revision		Revision as of 11:19, 9 August 2023
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	* [[Help:Conditional expressions]]		* [[Help:Conditional expressions]]
	* [[Relational operator]]		* [[Relational operator]]
	* [[Help:~~Magic_words~~#Variables]]		* {{section link\|Help:Magic words#Variables}}

	{{Wikipedia technical help\|collapsed}}		{{Wikipedia technical help\|collapsed}}

WOSlinker: syntaxhighlight lang="wikitext"

2023-05-09T07:50:36Z

syntaxhighlight lang="wikitext"

← Previous revision		Revision as of 07:50, 9 May 2023
Line 3:		Line 3:
	The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].		The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].

	Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not include the "Template:" prefix. {{tlc\|Template:Foobar}} also works, but "Template:" is not necessary. The result is "{{tlc\|Foobar}}".</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="~~moin~~" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.		Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not include the "Template:" prefix. {{tlc\|Template:Foobar}} also works, but "Template:" is not necessary. The result is "{{tlc\|Foobar}}".</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="wikitext" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.

	A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.		A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.
Line 10:		Line 10:
	The {{mono\|#switch}} function can be a one-line form:		The {{mono\|#switch}} function can be a one-line form:

	<syntaxhighlight lang=~~moin~~>		<syntaxhighlight lang="wikitext">
	{{#switch: {{{x}}} \|1=one \|2=two \|3\|4\|5=range 3–5 \|other}}		{{#switch: {{{x}}} \|1=one \|2=two \|3\|4\|5=range 3–5 \|other}}
	</syntaxhighlight>		</syntaxhighlight>
Line 37:		Line 37:
	== Using switches as if-elseif-elseif ==		== Using switches as if-elseif-elseif ==
	A #switch function can be structured as a set of pre-conditions which are tested until one is true (equal to "1"). For example to pre-screen numbers to avoid division by zero, in formula: {{code\|x/x2 + y/y2\|style=white-space:nowrap;}}		A #switch function can be structured as a set of pre-conditions which are tested until one is true (equal to "1"). For example to pre-screen numbers to avoid division by zero, in formula: {{code\|x/x2 + y/y2\|style=white-space:nowrap;}}
	<syntaxhighlight lang="~~moin~~">		<syntaxhighlight lang="wikitext">
	{{#switch: 1		{{#switch: 1
	\| {{#ifeq:{{{x2\|none}}}\|none\|1\|0}} = Parameter x2 has no data.		\| {{#ifeq:{{{x2\|none}}}\|none\|1\|0}} = Parameter x2 has no data.
Line 49:		Line 49:

	; Alphabetic data		; Alphabetic data
	: An alpha character string can be compared in the <code>#switch</code> by using <code>#ifeq:</code> {{nowrap\|as follows:{{nb5}}<syntaxhighlight lang="~~moin~~" inline>{{#ifeq:{{{x2\|none}}}\|none\|1\|0}}</syntaxhighlight>,}}		: An alpha character string can be compared in the <code>#switch</code> by using <code>#ifeq:</code> {{nowrap\|as follows:{{nb5}}<syntaxhighlight lang="wikitext" inline>{{#ifeq:{{{x2\|none}}}\|none\|1\|0}}</syntaxhighlight>,}}
	: where the result would be "1" when true, or "0" when false.		: where the result would be "1" when true, or "0" when false.
	; Numeric data		; Numeric data
	: Some numbers can be compared in the <code>#switch</code> by using <code>#expr:</code> {{nowrap\|as follows:{{nb5}}<syntaxhighlight lang="~~moin~~" inline>{{#expr: {{{y2}}} = 0}}</syntaxhighlight> or <syntaxhighlight lang="~~moin~~" inline>{{#expr: {{{x}}} < 41500}},</syntaxhighlight>}}		: Some numbers can be compared in the <code>#switch</code> by using <code>#expr:</code> {{nowrap\|as follows:{{nb5}}<syntaxhighlight lang="wikitext" inline>{{#expr: {{{y2}}} = 0}}</syntaxhighlight> or <syntaxhighlight lang="wikitext" inline>{{#expr: {{{x}}} < 41500}},</syntaxhighlight>}}
	: where each result would be "1" when true, or "0" when false.		: where each result would be "1" when true, or "0" when false.

	Another example, to test an amount "n" to determine the number of decimal digits:		Another example, to test an amount "n" to determine the number of decimal digits:
	<syntaxhighlight lang="~~moin~~">		<syntaxhighlight lang="wikitext">
	{{#switch: 1		{{#switch: 1
	\| {{#expr: floor({{{n}}}100) <> {{{n}}}100}} = 3		\| {{#expr: floor({{{n}}}100) <> {{{n}}}100}} = 3
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	Templates using such convoluted switch statements as to suffer significant performance issues should be translated to [[WP:Lua\|Lua]], if that will make them simpler or significantly faster. The below discussion should rarely be relevant but is preserved for reference.		Templates using such convoluted switch statements as to suffer significant performance issues should be translated to [[WP:Lua\|Lua]], if that will make them simpler or significantly faster. The below discussion should rarely be relevant but is preserved for reference.

	A #switch can contain over 1,000–2,000 branches, but should be split to have less than 100 branches, in multiple or nested parts. In some cases, it might be possible to split into multiple #switch structures, such as when many cases use the same first letter. Then, using <syntaxhighlight lang="~~moin~~" inline>{{padleft:\|1\|{{{value}}} }}</syntaxhighlight> can extract the first letter of <syntaxhighlight lang="~~moin~~" inline>{{{value}}}</syntaxhighlight> to be used in a higher #switch which branches by most-frequent letter, followed by all others at the bottom or "#default" branch. Another common split might be to separate numeric values into frequent ranges, followed by all other.		A #switch can contain over 1,000–2,000 branches, but should be split to have less than 100 branches, in multiple or nested parts. In some cases, it might be possible to split into multiple #switch structures, such as when many cases use the same first letter. Then, using <syntaxhighlight lang="wikitext" inline>{{padleft:\|1\|{{{value}}} }}</syntaxhighlight> can extract the first letter of <syntaxhighlight lang="wikitext" inline>{{{value}}}</syntaxhighlight> to be used in a higher #switch which branches by most-frequent letter, followed by all others at the bottom or "#default" branch. Another common split might be to separate numeric values into frequent ranges, followed by all other.

	The upper branches of a #switch execute faster, and the bottom branches must wait for comparisons of all higher branches. Hence, the top branch should be the most-used case, unless pre-screening of data is done in the early branches.		The upper branches of a #switch execute faster, and the bottom branches must wait for comparisons of all higher branches. Hence, the top branch should be the most-used case, unless pre-screening of data is done in the early branches.

MTOnline69: Undid revision 1134956746 by 216.24.76.219 (talk)

2023-01-27T19:42:18Z

Undid revision 1134956746 by 216.24.76.219 (talk)

← Previous revision		Revision as of 19:42, 27 January 2023
Line 3:		Line 3:
	The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].		The '''switch parser function''', coded as "'''#switch'''", selects the first matching branch in a list of choices, acting as a [[case statement]].

	Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not include the "Template:" prefix. {{tlc\|Template:Foobar}} also works, but "Template:" is not necessary. The result is "{{tlc\|Foobar}}".</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include boolean ~~expressions~~ to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="moin" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.		Each branch can be a [[value (computer science)\|value]], an [[expression (computer science)\|expression]] ([[Help:Calculation\|calculation]]), or a [[Wikipedia:Templates\|template]] call,<ref>A '''template call''' (also known as '''template tag''') has two "braces" on either side of the template page name and does not include the "Template:" prefix. {{tlc\|Template:Foobar}} also works, but "Template:" is not necessary. The result is "{{tlc\|Foobar}}".</ref> evaluated and compared to match the value of the switch. Although many #switch structures are used to branch among a simple set of values, the branches can also include [[boolean expression]]s to act as a set of pre-conditions to be tested until one tests true, acting as an ''if-elseif-elseif-elseif-else'' structure. The switch value is compared as a [[character string]], not a number, so "5" would not match "5.00" unless compared as <syntaxhighlight lang="moin" inline>"{{#expr:{{{1\|5.00}}} }}" (="5")</syntaxhighlight>.

	A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.		A #switch can contain over 1,000 branches, but for better speed should be split to have less than 100 branches, in each of multiple or nested parts. The upper branches execute faster, and the bottom branches must wait for comparisons of all higher branches. Because it is a [[wp:Parser function\|parser function]], a #switch can be used inside any page, even in article text, but in most cases, a #switch is typically used inside a [[wp:template\|template]], to branch depending on a [[Help:Template#Parameters\|parameter]] value passed to the template.
Line 72:		Line 72:
	Templates using such convoluted switch statements as to suffer significant performance issues should be translated to [[WP:Lua\|Lua]], if that will make them simpler or significantly faster. The below discussion should rarely be relevant but is preserved for reference.		Templates using such convoluted switch statements as to suffer significant performance issues should be translated to [[WP:Lua\|Lua]], if that will make them simpler or significantly faster. The below discussion should rarely be relevant but is preserved for reference.

	= A #switch can contain over 1,000–2,000 branches, but should be split to have less than 100 branches, in multiple or nested parts. In some cases, it might be possible to split into multiple #switch structures, such as when many cases use the same first letter. Then, using <syntaxhighlight lang="moin" inline~~=""~~>{{padleft:\|1\|{{{value}}} }}</syntaxhighlight> can extract the first letter of <syntaxhighlight lang="moin" inline~~=""~~>{{{value}}}</syntaxhighlight> to be used in a higher #switch which branches by ~~[[Reset\|~~most]]-frequent letter, followed by all others at the bottom or "#default" branch. Another common split might be to separate numeric values into frequent ranges, followed by all other. =		A #switch can contain over 1,000–2,000 branches, but should be split to have less than 100 branches, in multiple or nested parts. In some cases, it might be possible to split into multiple #switch structures, such as when many cases use the same first letter. Then, using <syntaxhighlight lang="moin" inline>{{padleft:\|1\|{{{value}}} }}</syntaxhighlight> can extract the first letter of <syntaxhighlight lang="moin" inline>{{{value}}}</syntaxhighlight> to be used in a higher #switch which branches by most-frequent letter, followed by all others at the bottom or "#default" branch. Another common split might be to separate numeric values into frequent ranges, followed by all other.

	The upper branches of a #switch execute faster, and the bottom branches must wait for comparisons of all higher branches. Hence, the top branch should be the most-used case, unless pre-screening of data is done in the early branches.		The upper branches of a #switch execute faster, and the bottom branches must wait for comparisons of all higher branches. Hence, the top branch should be the most-used case, unless pre-screening of data is done in the early branches.

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	* [[Help:Magic_words#Variables]]		* [[Help:Magic_words#Variables]]

	{{Wikipedia technical help}}		{{Wikipedia technical help\|collapsed}}