幫助:扩展:解析器函數

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扩展:解析器函数 扩展提供11个額外的解析器函数以补充MediaWiki固有的“魔术字 ”。 (它有可能会配置到增加的解析器函数以支持运行:这些字符串函数已在其他文档页面 记载。) 所有的解析器函数由下列的表格提供。

{{#函数名: 参数1 | 参数2 | 参数3... }}

#expr

类型 运算符号
分组(括弧) ( )
数字 1234.5   e (2.718)   pi (3.142)
二进制运算符 e   一元 +,-
一元 not ceil trunc floor abs exp ln sin cos tan acos asin atan
二进制 ^
* / div mod
+ -
取整 round
逻辑 = != <> > < >= <=
and
or

这个函数计算并返回数学表达式的结果。 这个函数也通过mw.ext.ParserFunctions.expr函数中在扩展:Scribunto 有效。

{{#expr: 表达式 }}

右表依优先级列出了支持的运算符,运算符的详细说明请见Help:Calculation。运算结果的精度和格式受服务器操作系统及语言设置影响可能存在差异。

使用布尔代数时,0表示false,其他任何非0数值(无论正负)均表示true

{{#expr: 1 and -1 }}1
{{#expr: 1 and 0 }}0
{{#expr: 1 or -1 }}1
{{#expr: -1 or 0 }}1
{{#expr: 0 or 0 }}0

空表达式返回空值,错误的表达式返回错误信息,使用#iferror函数检查错误:

{{#expr: }}
{{#expr: 1+ }}Expression error: Missing operand for +.
{{#expr: 1 = }}Expression error: Missing operand for =.
{{#expr: 1 foo 2 }}Expression error: Unrecognized word "foo".

置于数字前的加减号会被视为正负号而不会报错:

{{#expr: +1 }}1
{{#expr: -1 }}-1
{{#expr: + 1 }}1
{{#expr: - 1 }}-1

注意:使用魔术字输出的数值时,首先要将其格式化以去除逗号,获得纯数字。例如:{{NUMBEROFUSERS}}输出17,388,789,而期望的输出值是17388789,使用{{formatnum :{{NUMBEROFUSERS}}|R}}便可以实现。对于某些语言,格式化数字尤为重要。例如孟加拉语中,{{NUMBEROFUSERS}}的输出结果是৩০,০৬১。

{{#expr:{{NUMBEROFUSERS}}+100}} Expression error: Unrecognized punctuation character ",".
{{#expr:{{formatnum:{{NUMBEROFUSERS}}|R}}+100}}17388889
警告 警告: 运算符mod會對第二參數的某些值給出錯誤的结果:
{{#expr: 123 mod (2^64-1)}}Division by zero. (輸出一個空值;應該是123)
如果你想要进行基于日期时间的计算(如检测当前日期时间是否超过指定日期时间),首先用{{#time: xNU }}将日期时间转换为距1970年1月1日的秒数,再对秒数进行加减运算。

四舍五入

a round b是指将a四舍五入至(1/10)b的整数倍。

向上、向下取整分别使用ceilfloor

案例 结果 凑整方式
{{#expr: 1/3 round 5 }} 0.33333 最终的数字小于5,所以没有明显的取整发生
{{#expr: 1/6 round 5 }} 0.16667 最终的数字大于5,所以被向上取整
{{#expr: 8.99999/9 round 5 }} 1 同理,最后一位数因后一位而加1,进而引起了前面的进位
{{#expr: 1234.5678 round -2 }} 1200 舍入至最近的整百数,负值在小数点左边。
{{#expr: 1234.5678 round 2 }} 1234.57 舍入至最近的整1/100数,因为正值会舍入至小数点右边。
{{#expr: 1234.5678 round 2.3 }} 1234.57 舍入指数的小数点在舍入结果中不起作用
{{#expr: trunc 1234.5678 }} 1234 小数部分被全部舍弃(截断)
四舍五入至最近的整数
{{#expr: 1/3 round 0 }} 0 向下取整至0
{{#expr: 1/2 round 0 }} 1 向上取整至1
{{#expr: 3/4 round 0 }} 1 向上取整至1
{{#expr: -1/3 round 0 }} -0 向上取整至0
{{#expr: -1/2 round 0 }} -1 向下取整至-1
{{#expr: -3/4 round 0 }} -1 向下取整至-1
使用ceil和floor向上或向下取整
{{#expr: ceil(1/3) }} 1 向上取整至1
{{#expr: floor(1/3) }} 0 向下取整至0
{{#expr: ceil(-1/3) }} -0 向上取整至0
{{#expr: floor(-1/3) }} -1 向下取整至-1
{{#expr: ceil 1/3 }} 0.33333333333333 没有取整,因为1本来就是整数
警告 警告: 注意会被解析为(ceil 1)/3,而不是你想象中的ceil(1/3)

字符串

表达式函数只用于仅含有数字和运算符号的表达式,而字母字符串和其它符号不在此列。若需要比较字符串,可以用#ifeq替代。

{{#expr: "a" = "a" }}Expression error: Unrecognized punctuation character """.
{{#expr: a = a }}Expression error: Unrecognized word "a".
{{#ifeq: a | a | 1 | 0 }}1

#if

这个函数判断一个字符串是否为空。只包含空格的字符串被视为空字符串。

{{#if: 测试字符串 | 当测试字符串不是空值时的值 | 当测试字符串是空值(或只包括空格)时的值 }}
{{#if: 参数1 | 参数2 | 参数3 }}

这个函数首先判断参数1是否为空。如果参数1不为空,则输出参数2。如果参数1为空或只包含空白内容(空格、换行等),则输出参数3。

{{#if: | yes | no}}no
{{#if: string | yes | no}}yes
{{#if:      | yes | no}}no
{{#if:


| yes | no}}
no

字符串内容会被处理为纯文本,因此数学表达式不会被计算:

{{#if: 1==2 | yes | no }}yes
{{#if: 0 | yes | no }}yes

最后一个参数(false)可以被忽略:

{{#if: foo | yes }} yes
{{#if: | yes }}
{{#if: foo | | no}}

该函数可嵌套。为了做到这一点,嵌套内层的#if函数需要按规则完整填写所有参数以符合#if的参数形式。一般至多可嵌套7层,该数也可能为wiki自身限制和内存限制而有变动。

{{#if: 测试字符串 | 字符串非空时的值 | {{#if: 测试字符串 | 字符串非空时的值 | 字符串为空(或只有空格)的值 }} }}

你可以在#if条件句中以字符串变量代替测试字符串。在这里,你需要在变量名的后面加上| (分隔符)以正确引用字符串。 (因此如果参数是空值,它计算结果为一个空字符而非"{{{1}}}")

{{#if:{{{1|}}}|你在变量1里面输入了文本|变量1里面没有文本 }}

在这里 Help:Parser functions in templates 获得更多关于解释器函数中变量的相关例子。

#ifeq

这个函数判断两个輸入字符串是否相同,並根據結果輸出兩個字符串的其中一個。 如果需要更多的比較和輸出字符串,請考慮使用#switch

{{#ifeq: string 1 | string 2 | value if identical | value if different }}

如果两个字符串均为数字,则函数会进行数值的比较:

{{#ifeq: 01 | 1 | equal | not equal}}equal
{{#ifeq: 0 | -0 | equal | not equal}}equal
{{#ifeq: 1e3 | 1000 | equal | not equal}}equal
{{#ifeq: {{#expr:10^3}} | 1000 | equal | not equal}}equal

否则函数会进行文本的比较(大小写敏感):

{{#ifeq: foo | bar | equal | not equal}}not equal
{{#ifeq: foo | Foo | equal | not equal}}not equal
{{#ifeq: "01" | "1" | equal | not equal}}not equal  (对比上面没有引号的例子)
{{#ifeq: 10^3 | 1000 | equal | not equal}}not equal  (对比上面带有#expr的例子,會先回傳一個有效的整數)

作为例子,考虑一个已经存在着的模板 Template:Timer,该模板利用解析器来選擇兩個標準時間,short和long。 它以参数作为第一个输入来比较字符串“short”–这没有约定顺序,但是如果参数在第一个则更容易理解。 模板代码定义为:

{{#ifeq: {{{1|}}} | short | 20 | 40 }}

会产生如下结果:

{{timer|short}}20
{{timer|20}}40
{{timer}}40
警告 警告: 在数值比较结果上,#ifexpr不总是和解释器#ifeq#switch保持一致。 后面两种比较相对于#ifexpr而言更加精确,因而未必返回相同结果。

考虑比较下面两个仅有最后一个数码不同的数:

{{#ifeq: 12345678901234567 | 12345678901234568 | equal | not equal}}not equal
{{#switch: 12345678901234567 | 12345678901234568 = equal | not equal}}not equal

因为用于#ifeq#switch的PHP用整数类型比较两个数,它会正确返回预期结果。 然而用#ifexpr比较相同的两个数时:

{{#ifexpr: 12345678901234567 = 12345678901234568 | equal | not equal}}equal

对于不同的数字,结果实际上是不正确的。

由于两个数存在不相同的数位,相等比较的结果显然是“错误的”。造成#ifexpr出错行为的原因是MediaWiki将两个数依字面表达理解成了浮点数,而对于像这样的大数,转换为浮点数由于精度误差会存储为一样的数值,导致出错。

警告 警告: 如果比较参数使用了解释器函数,任何的解释器标记和其它的解释器函数都一定会被一个临时生成的独一无二的标识码 所替代。这会影响如下列的比较:
{{#ifeq: <nowiki>foo</nowiki> | <nowiki>foo</nowiki> | equal | not equal}}not equal
{{#ifeq: <math>foo</math> | <math>foo</math> | equal | not equal}}not equal
{{#ifeq: {{#tag:math|foo}} | {{#tag:math|foo}} | equal | not equal}}not equal
{{#ifeq: [[foo]] | [[foo]] | equal | not equal}}equal
如果被比较字符串从所使用的模板 到模板内使用的参数和标记都是相同的,那么这种情况下会返回真值,但如果所使用模板名不同,即便内容是完全一致的,判断也会返回假值。
警告 警告: 随网站配置的变化,含有页面名字的魔术字 的字符串的字面比较可能会发生错误。 比如说,{{FULLPAGENAME}}这一魔术字随wiki的变化,可能在返回时使开头字母变成大写,也会用下划线替代空格。

为了解决这个问题,将这个魔术字应用到两个参数上:

{{#ifeq: {{FULLPAGENAME: L'Aquila}} | {{FULLPAGENAME}} | equal | not equal}}equal

#iferror

这个函数以一个字符串为输入,然后在两条预选结果中取其一而返回。函数认定为true当且仅当作为输入参数的字符串在解释时返回的结果中含有一个class="error"的HTML对象,而其中可用来认定结果的包括其他的解释器函数(比如#expr#time#rel2abs)的错误,模板错误(比如模板循环和模板递归),还有一些其它的解释器“软错误”。

{{#iferror: test string | value if error | value if correct }}

待返回字符串参数可以省略。若省略"correct"(正确)字符串参数,则在"test string"(测试字符串)不出错的情况下函数将返回被测字符串本身。若省略"error"(错误)字符串参数,则函数将在被测字符串出错时返回空字符串:

{{#iferror: {{#expr: 1 + 2 }} | error | correct }}correct
{{#iferror: {{#expr: 1 + X }} | error | correct }}error
{{#iferror: {{#expr: 1 + 2 }} | error }}3
{{#iferror: {{#expr: 1 + X }} | error }}error
{{#iferror: {{#expr: 1 + 2 }} }}3
{{#iferror: {{#expr: 1 + X }} }}
{{#iferror: {{#expr: . }} | error | correct }}correct
{{#iferror: <strong class="error">a</strong> | error | correct }}error

#ifexpr

此函数会判断数学表达式并根据其布尔值结果返回对应的字符串:

{{#ifexpr: expression | value if true | value if false }}

这里"expression"输入串将原封不动的作为上面#expr的参数进行调用,且表达式运算符是通用的,返回值也将作为布尔表达式进行处理。

输入表达式为空时将视为false

{{#ifexpr: | yes | no}}no

如上面所提,0将视为false,非零值将视为true,因此这个函数与下面的仅用#ifeq#expr的表述等价:

{{#ifeq: {{#expr: expression }} | 0 | value if false | value if true }}

除了下面这种情况:所输入表达式为空或者是一个错误表达式(空串会返回一条错误信息,而它不等于0,所以在后者我们会得到"value if true")。

{{#ifexpr: = | yes | no }} Expression error: Unexpected = operator.

相对的

{{#ifeq: {{#expr: = }} | 0 | no | yes }} yes

两个待选返回值都不是必填的。当表达式判断对应的分支返回值被省略时,函数不会给出输出:

{{#ifexpr: 1 > 0 | yes }}yes
{{#ifexpr: 1 < 0 | yes }}
{{#ifexpr: 0 = 0 | yes }} yes
{{#ifexpr: 1 > 0 | | no}}
{{#ifexpr: 1 < 0 | | no}} no
{{#ifexpr: 1 > 0 }}

#ifexist

这个函数将一组字符串作为输入,并翻译成页面标题,然后根据在本地wiki上是否存在该页面而返回对应的值。

{{#ifexist: page title | value if exists | value if doesn't exist }}

只要页面存在就会判定为true(真值),即便那个页面看上去是空白的(比如像是分类链接或者是魔术字 解释页之类的却不包含任何可视内容的页面),或者是重定向页 ,或者它就是空白页。当且仅当页面是红链时判定为false(假值),包括那些曾经存在却被删除的页面。

{{#ifexist: Help:Extension:ParserFunctions/zh | exists | doesn't exist }}exists
{{#ifexist: XXHelp:Extension:ParserFunctions/zhXX | exists | doesn't exist }}doesn't exist

函数在系统消息 对应模块被安装时认定为true,对特殊页面 的判定则取决于本地软件自身。

{{#ifexist: Special:Watchlist | exists | doesn't exist }}exists
{{#ifexist: Special:CheckUser | exists | doesn't exist }}exists (因为Checkuser 扩展已经安装于此wiki)
{{#ifexist: MediaWiki:Copyright | exists | doesn't exist }}exists (因为MediaWiki:Copyright未自定义)

如果一个页面使用了#ifexist:来检查目标页面,则这个检查页面将出现在被检查页面的Special:WhatLinksHere里。所以如果本页面(Help:Extension:ParserFunctions/zh)使用了代码 {{#ifexist:Foo ,那么[[{{#special:WhatLinksHere}}/Foo]]将列出{{FULLPAGENAME}}。 若wiki有其在使用的对应的共享媒体库,<code>#ifexist:</code>就可用于检查一个文件是否在媒体库中,而不仅仅只是在wiki本体上检查: :<code><nowiki>{{#ifexist: File:Example.png | exists | doesn't exist }}doesn't exist

{{#ifexist: Image:Example.png | exists | doesn't exist }}doesn't exist
{{#ifexist: Media:Example.png | exists | doesn't exist }}exists

如果文件有一个已创建的对应的本地描述页面,上面的结果将全部是exists

#ifexist: 不会对维基内链起作用。

ifexist 限制

#ifexist:被视为一个“高配额解释器函数”,每个页面调用这类函数的次数(包括包含于嵌入式模板的函数)存在一个限制。当达到该限制时,对于多出该限制的#ifexist:函数,无论其目标页面是否存在,函数只会自动返回错误值false,且该页面会被分类为Category:Pages with too many expensive parser function calls中。追踪分类 可能因您的wiki内容的语言而异。

在某些案例中,在css中,利用选择器a.new(以选出导向不存在页面的链接)或者是a:not(.new)(以选出已存在页面的链接),是可以达到模仿ifexist的效果的。另外,通过控制$wgExpensiveParserFunctionLimit 可以调整对高配额解释器函数数量的限制,如果有需要,也可以增加页面LocalSettings.php中的限制值。

ifexisit和待创建页面

一个不存在的页面被#ifexist检测后会被计数在 待创建页面中。

#rel2abs

这个函数将文件的相对路径转换为绝对路径。

{{#rel2abs: path }}
{{#rel2abs: path | base path }}

在输入项path中,可以使用以下类型的句法:

  • . → 本级路径
  • .. → 回到上一级
  • /foogo down one level into the subdirectory /foo

base path没有指定,将默认的填入函数所在页面的绝对路径:

{{#rel2abs: /quok | Help:Foo/bar/baz }}Help:Foo/bar/baz/quok
{{#rel2abs: ./quok | Help:Foo/bar/baz }}Help:Foo/bar/baz/quok
{{#rel2abs: ../quok | Help:Foo/bar/baz }}Help:Foo/bar/quok
{{#rel2abs: ../. | Help:Foo/bar/baz }}Help:Foo/bar

形如/././的不合理的句法将被忽略。 连用至多两个句点(如:..<\code>)是可以的,语句会被正确的分割成可成功执行的情况:

{{#rel2abs: ../quok/. | Help:Foo/bar/baz }}Help:Foo/bar/quok
{{#rel2abs: ../../quok | Help:Foo/bar/baz }}Help:Foo/quok
{{#rel2abs: ../../../quok | Help:Foo/bar/baz }}quok
{{#rel2abs: ../../../../quok | Help:Foo/bar/baz }}Error: Invalid depth in path: "Help:Foo/bar/baz/../../../../quok" (tried to access a node above the root node).

#switch

See also : w:Help:Switch parser function

该函数将一个输入值同若干个预备判断值做比较,并在相等比较成立的时候返回分支对应的字符串。

{{#switch: comparison string
 | case = result
 | case = result
 | ...
 | case = result
 | default result
}}

例如:

{{#switch: baz | foo = Foo | baz = Baz | Bar }} Baz
{{#switch: foo | foo = Foo | baz = Baz | Bar }} Foo
{{#switch: zzz | foo = Foo | baz = Baz | Bar }} Bar

含有部分嵌入包含标记的#switch会影响到一个配置文件,这可能会引起想要查看和更改配置元素的模板编写者的陌生感。

默认

comparison string(被匹配串)不能与任何预设case相匹配时,就会进入default(默认/缺省)分支并返回default result(默认返回值):

{{#switch: test | foo = Foo | baz = Baz | Bar }} Bar

如以下情形,默认返回值必须是函数的最后一个参数,而且不能包含原始等号(不帶{{}}的等號)。 If it does, it will be treated as a case comparison, and no text will display if no cases match. This is because the default value has not been defined (is empty). If a case matches however, its associated string will be returned.

{{#switch: test | Bar | foo = Foo | baz = Baz }} →
{{#switch: test | foo = Foo | baz = Baz | B=ar }} →
{{#switch: test | test = Foo | baz = Baz | B=ar }} → Foo

取而代之的是,默认返回值可以显式的用#default来作为一条"case"进行声明。

{{#switch: comparison string
 | case = result
 | case = result
 | ...
 | case = result
 | #default = default result
}}

利用这种方法,默认返回值的显式声明可以在函数的任意一个地方被使用:

{{#switch: test | foo = Foo | #default = Bar | baz = Baz }} Bar

如果忽略了"default"(默认)参数,函数会在不匹配的时候什么也不返回:

{{#switch: test | foo = Foo | baz = Baz }}

组状态

该函数允许存在'fall through'现象(多个"case"值使用同一个"result"串)。这可以减少重复。

{{#switch: comparison string
 | case1 = result1
 | case2 
 | case3 
 | case4 = result234
 | case5 = result5
 | case6 
 | case7 = result67
 | #default = default result
}}

在本例中,第二、三、四个分支都会返回"result234",第六和第七个分支都会返回"result67"The "#default = " in the last parameter may be omitted in the above case.

Use with parameters

The function may be used with parameters as the test string. In this case, it is not necessary to place the pipe after the parameter name, because it is very unlikely that you will choose to set a case to be the string "{{{parameter name}}}". (This is the value the parameter will default to if the pipe is absent and the parameter doesn't exist or have a value. 参见Help:Parser functions in templates 。)

{{#switch: {{{1}}} | foo = Foo | baz = Baz | Bar }}

In the above case, if {{{1}}} equals foo, the function will return Foo. If it equals baz, the function will return Baz. If the parameter is empty or does not exist, the function will return Bar.

As in the section above, cases can be combined to give a single result.

{{#switch: {{{1}}} | foo | zoo | roo = Foo | baz = Baz | Bar }}

Here, if {{{1}}} equals foo, zoo or roo, the function will return Foo. If it equals baz, the function will return Baz. If the parameter is empty or does not exist, the function will return Bar.

Additionally, the default result can be omitted if you do not wish to return anything if the test parameter value does not match any of the cases.

{{#switch: {{{1}}} | foo = Foo | bar = Bar }}

In this case, the function returns an empty string unless {{{1}}} exists and equals foo or bar, in which case it returns Foo or Bar, respectively.

This has the same effect as declaring the default result as empty.

{{#switch: {{{1}}} | foo | zoo | roo = Foo | baz = Baz | }}

If for some reason you decide to set a case as "{{{parameter name}}}", the function will return that case's result when the parameter doesn't exist or doesn't have a value. The parameter would have to exist and have a value other than the string "{{{parameter name}}}" to return the function's default result.

(when {{{1}}} doesn't exist or is empty):
{{#switch: {{{1}}} | {{{1}}} = Foo | baz = Baz | Bar }} Foo
(when {{{1}}} has the value "test"):
{{#switch: {{{1}}} | {{{1}}} = Foo | baz = Baz | Bar }} Bar
(when {{{1}}} has the value "{{{1}}}"):
{{#switch: {{{1}}} | {{{1}}} = Foo | baz = Baz | Bar }} Foo


In this hypothetical case, you would need to add the pipe to the parameter ({{{1|}}}).

比较行为

如同#ifeq那样,若被比较串和测试条件串都是数字串的,那么将之按照数字进行比较;反之若存在一个非纯数字串,都会按照字符串比较规则进行:

{{#switch: 0 + 1 | 1 = one | 2 = two | three}} → three
{{#switch: {{#expr: 0 + 1}} | 1 = one | 2 = two | three}} → one
{{#switch: a | a = A | b = B | C}} → A
{{#switch: A | a = A | b = B | C}} → C

一个case串可以是空的:

{{#switch: | = Nothing | foo = Foo | Something }}Nothing

顺序的,只要有一个case匹配中了,其它的都会被忽略:

{{#switch: b | f = Foo | b = Bar | b = Baz | }}Bar
警告 警告: #switch#ifeq的数值比较结果未必一致(参见上面#ifeq部分):
{{#switch: 12345678901234567 | 12345678901234568 = A | B}} → B
{{#ifexpr: 12345678901234567 = 12345678901234568 | A | B}} → A

原始等号

"Case"测试条件串中不能包含原始等号。如果需要在比较串中加入等号,可以使用仅包含一个等号的模板{{=}}来代替=,或者是用HTML标识码&#61;来代替。

例如:

{{#switch: 1=2
 | 1=2 = raw
 | 1<nowiki>=</nowiki>2 = nowiki
 | 1{{=}}2 = template
 | default
}}template


{{#switch: 1=2
 | 1&#61;2 = html
 | default
}}html

为助您理解,您可以检查[[1]]。模板:扩展 w:Template:BOTREQ是两个使用该函数的复杂例子。

替换#ifeq

#switch可以用于迭代深度.

例如:

  • {{#switch:{{{1}}} |condition1=branch1 |condition2=branch2 |condition3=branch3 |branch4}}

等效于

  • {{#ifeq:{{{1}}}|condition1 |branch1 |{{#ifeq:{{{1}}}|condition2 |branch2 |{{#ifeq:{{{1}}}|condition3 |branch3 |branch4}}}}}}

也就是线性的深度迭代判断:

{{#ifeq:{{{1}}}|condition1
  |<!--then-->branch1
  |<!--else-->{{#ifeq:{{{1}}}|condition2
                |<!--then-->branch2
                |<!--else-->{{#ifeq:{{{1}}}|condition3
                              |<!--then-->branch3
                              |<!--else-->branch4}}}}}}

但同时,用switch代替嵌套的IF语句有可能会使语句变得更为复杂,甚至弄巧成拙,例如下面的这个例子,IF语句构成了一棵对称的决策树,相应对称的部分已经用缩进和注释标齐:

{{#ifeq:{{{1}}}|condition1
 |<!--then-->branch1t{{
  #ifeq:{{{1}}}|condition2
   |<!--then-->branch1t2t{{#ifeq:{{{1}}}|condition4|<!--then-->branch1t2t4t|<!--else-->branch1t2t4e}}
   |<!--else-->branch1t2e{{#ifeq:{{{1}}}|condition5|<!--then-->branch1t2e5t|<!--else-->branch1t2e5e}}
  }}
 |<!--else-->branch1e{{#ifeq:{{{1}}}|condition3
   |<!--then-->branch1e3t{{#ifeq:{{{1}}}|condition6|branch1e3t6t|branch1e3t6e}}
   |<!--else-->branch1e3e{{
    #ifeq:{{{1}}}|condition7
     |branch1e3e7t
     |branch1e3e7t
    }}
  }}
}}

#time

This parser function takes a date and/or time (in the Gregorian calendar) and formats it according to the syntax given. A date/time object can be specified; the default is the value of the magic word {{CURRENTTIMESTAMP}} – that is, the time the page was last rendered into HTML.

{{#time: format string }}
{{#time: format string | date/time object }}
{{#time: format string | date/time object | language code }}
{{#time: format string | date/time object | language code | local }}

The list of accepted formatting codes is given in the table to the right. Any character in the formatting string that is not recognized is passed through unaltered; this applies also to blank spaces (the system does not need them for interpreting the codes). There are also two ways to escape characters within the formatting string:

  1. A backslash followed by a formatting character is interpreted as a single literal character
  2. Characters enclosed in double quotes are considered literal characters, and the quotes are removed.

In addition, the digraph xx is interpreted as a single literal "x".

{{#time: Y-m-d }}2020-10-27
{{#time: [[Y]] m d }}2020 10 27
{{#time: [[Y (year)]] }}2020 (20UTCpmTue, 27 Oct 2020 19:00:05 +0000)
{{#time: [[Y "(year)"]] }}2020 (year)
{{#time: i's" }}00'05"

The date/time object can be in any format accepted by PHP's strtotime() function. Both absolute (eg 20 December 2000) and relative (eg +20 hours) times are accepted.

{{#time: r|now}}Tue, 27 Oct 2020 19:00:06 +0000
{{#time: r|+2 hours}}Tue, 27 Oct 2020 21:00:06 +0000
{{#time: r|now + 2 hours}}Tue, 27 Oct 2020 21:00:06 +0000
{{#time: r|20 December 2000}}Wed, 20 Dec 2000 00:00:00 +0000
{{#time: r|December 20, 2000}}Wed, 20 Dec 2000 00:00:00 +0000
{{#time: r|2000-12-20}}Wed, 20 Dec 2000 00:00:00 +0000
{{#time: r|2000 December 20}}Error: Invalid time.

The language code in ISO 639-3 (?) allows the string to be displayed in the chosen language

{{#time:d F Y|1988-02-28|nl}}28 februari 1988
{{#time:l|now|uk}}вівторок
{{#time:d xg Y|20 June 2010|pl}}20 czerwca 2010

The local parameter specifies if the date/time object refers to the local timezone or to UTC.

This is a boolean parameters: its value is determined by casting the value of the argument (see the official PHP documentation for details on how string are cast to boolean values).

Please note that, if the variable $wgLocaltimezone is set to UTC, there is no difference in the output when local is set to true or false.

See the following examples for details:

{{#time: Y F d H:i:s|now|it|0}}2020 ottobre 27 19:00:06
{{#time: Y F d H:i:s|now|it|1}}2020 ottobre 27 19:00:06
{{#time: Y F d H:i:s|+2 hours||0}}2020 10月 27 21:00:06
{{#time: Y F d H:i:s|+2 hours||1}}2020 10月 27 21:00:06
{{#time:c|2019-05-16T17:05:43+02:00|it}}2019-05-16T15:05:43+00:00
{{#time:c|2019-05-16T17:05:43+02:00|it|0}}2019-05-16T15:05:43+00:00
{{#time:c|2019-05-16T17:05:43+02:00|it|true}}2019-05-16T15:05:43+00:00

If you've calculated a Unix timestamp, you may use it in date calculations by pre-pending an @ symbol.

{{#time: U | now }}1603825206
{{#time: r | @1603825205 }}Tue, 27 Oct 2020 19:00:05 +0000
警告 警告: 若不在數字格式的時間戳值的前面包含@前綴,結果通常會出錯或是未預期的數值:
{{#time: r | 1970-01-01 00:16:39 }}Thu, 01 Jan 1970 00:16:39 +0000
{{#time: U | 1970-01-01 00:16:39 }}999
{{#time: r | @999 }}Thu, 01 Jan 1970 00:16:39 +0000 (正確)
{{#time: r | 999 }}Error: Invalid time. (不支援的年分格式)
{{#time: r | 1970-01-01 00:16:40 }}Thu, 01 Jan 1970 00:16:40 +0000
{{#time: U | 1970-01-01 00:16:40 }}1000
{{#time: r | @1000 }}Thu, 01 Jan 1970 00:16:40 +0000 (正確)
{{#time: r | 1000 }}Mon, 27 Oct 1000 00:00:00 +0000 (被解讀為某年的目前月分和日期)
{{#time: r | 1970-01-01 02:46:39 }}Thu, 01 Jan 1970 02:46:39 +0000
{{#time: U | 1970-01-01 02:46:39 }}9999
{{#time: r | @9999 }}Thu, 01 Jan 1970 02:46:39 +0000 (正確)
{{#time: r | 9999 }}Wed, 27 Oct 9999 00:00:00 +0000 (被解讀為某年的目前月分和日期)
{{#time: r | 1970-01-01 02:46:40 }}Thu, 01 Jan 1970 02:46:40 +0000
{{#time: U | 1970-01-01 02:46:40 }}10000
{{#time: r | @10000 }}Thu, 01 Jan 1970 02:46:40 +0000 (正確)
{{#time: r | 10000 }}Error: Invalid time. (不支援的年分格式)
警告 警告:

The range of acceptable input is 1 January 0111 → 31 December 9999. For the years 100 through 110 the output is inconsistent, Y and leap years are like the years 100-110, r, D, l and U are like interpreting these years as 2000-2010.

{{#time: d F Y | 29 Feb 0100 }}01 3月 0100
(正確,沒有閏年),但是
{{#time: r | 29 Feb 0100 }}Mon, 01 Mar 0100 00:00:00 +0000 (錯誤,100被解讀為2000,但那是閏年)
{{#time: d F Y | 15 April 10000 }}Error: Invalid time.
{{#time: r | 10000-4-15 }}Sat, 15 Apr 2000 10:00:00 +0000

Year numbers 0-99 are interpreted as 2000-2069 and 1970-1999, except when written in 4-digit format with leading zeros:

{{#time: d F Y | 1 Jan 6 }}01 1月 2006
{{#time: d F Y | 1 Jan 06 }}01 1月 2006
{{#time: d F Y | 1 Jan 006 }}01 1月 2006
{{#time: d F Y | 1 Jan 0006 }}01 1月 0006 (4-digit format)

The weekday is supplied for the years 100-110 and from 1753, for the years 111-1752 the r-output shows "Unknown" and the l-output "<>". As a consequence, the r-output is not accepted as input for these years.

Full or partial absolute dates can be specified; the function will "fill in" parts of the date that are not specified using the current values:

{{#time: Y | January 1 }}2020
警告 警告:

The fill-in feature is not consistent; some parts are filled in using the current values, others are not:

{{#time: Y m d H:i:s | June }}2020 06 27 00:00:00 Gives the start of the day, but the current day of the month and the current year.
{{#time: Y m d H:i:s | 2003 }}2003 10 27 00:00:00 Gives the start of the day, but the current day of the year.

There's exception case of the filled day:

{{#time: Y m d H:i:s | June 2003 }}2003 06 01 00:00:00 Gives the start of the day and the start of the month.

4位數字總是被解讀為年分,而不是小時和分鐘:[1]

{{#time: Y m d H:i:s | 1959 }}1959 10 27 00:00:00

6位數字盡量被解讀為小時、分鐘、秒,不然會被解讀為錯誤(而不是年分和月分):

{{#time: Y m d H:i:s | 195909 }}2020 10 27 19:59:09 輸入被視為時間而不是年+月代碼。
{{#time: Y m d H:i:s | 196009 }}Error: Invalid time. 雖然19:60:09不是有效時間,但196009不被解讀為1960年9月。

該函數執行一定數量的日期算數:

{{#time: d F Y | January 0 2008 }}31 12月 2007
{{#time: d F | January 32 }}Error: Invalid time.
{{#time: d F | February 29 2008 }}29 2月
{{#time: d F | February 29 2007 }}01 3月
{{#time:Y-F|now -1 months}}2020-9月

#time調用的格式字符串的總長度限制為6000個字符[2]

时区问题

There is a bug in this #time parser function (more specifically in PHP DateTime) that does not allow the passing-in of non-integers as relative time zone offsets. This issue does not apply when using an on-the-hour time zone, such as EDT. For example:

  • {{#time:g:i A | -4 hours }} → 3:00 PM

However, India is on a +5.5 hours time offset from UTC, and thus using its time zone will not normally allow the correct calculation of a relative time zone offset. Here's what happens:

  • {{#time:g:i A | +5.5 hours }} → 7:00 PM

To workaround this issue, simply convert the time into minutes or seconds, like this:

  • {{#time:g:i A | +330 minutes }} → 12:30 AM
  • {{#time:g:i A | +19800 seconds }} → 12:30 AM

(Tim Starling, the developer of this function, provided the exact syntax for this solution.)

#timel

This function is identical to {{#time: ... }}, when the local parameter is set to true, so it always uses the local time of the wiki (as set in $wgLocaltimezone ).

Syntax of the function is:

{{#timel: format string }}
{{#timel: format string | date/time object }}
{{#timel: format string | date/time object | language code }}

Please note that, if the variable $wgLocaltimezone is set to UTC, there is no difference in the output when local is set to true or false
Example of the use of #time and #timel parser functions from a server where the timezone is not UTC

For instance, see the following examples:

{{#time:c|now|it}}2020-10-27T19:00:06+00:00
{{#time:c|now|it|0}}2020-10-27T19:00:06+00:00
{{#time:c|now|it|1}}2020-10-27T19:00:06+00:00
{{#timel:c|now|it}}2020-10-27T19:00:06+00:00
警告 警告:

Be aware that U for both time and timel will return the same number of seconds since 1970-01-01 00:00:00 UTC on Wikipedias with different timezones than UTC (formerly known as GMT)

U Unix时间。自1970年1月1日 00:00:00(GMT)以来的秒数。
Z 时区偏移(秒)。
{{#time: U}}1603825205
{{#timel: U}}1603825205
{{#time: Z}}0
{{#timel: Z}}0

#titleparts

This function separates a page title into segments based on slashes, then returns some of those segments as output.

{{#titleparts: pagename | number of segments to return | first segment to return }}

If the number of segments to return parameter is not specified, it defaults to "0", which returns all the segments from the first segment to return (included). If the first segment to return parameter is not specified or is "0", it defaults to "1":

{{#titleparts: Talk:Foo/bar/baz/quok }}Talk:Foo/bar/baz/quok
{{#titleparts: Talk:Foo/bar/baz/quok | 1 }}Talk:Foo See also {{ROOTPAGENAME }}.
{{#titleparts: Talk:Foo/bar/baz/quok | 2 }}Talk:Foo/bar
{{#titleparts: Talk:Foo/bar/baz/quok | 2 | 2 }}bar/baz
{{#titleparts: Talk:Foo/bar/baz/quok | | 2 }}bar/baz/quok
{{#titleparts: Talk:Foo/bar/baz/quok | | 5 }}

Negative values are accepted for both values. Negative values for the number of segments to return parameter effectively 'strips' segments from the end of the string. Negative values for the first segment to return translates to "start with this segment counting from the right":

{{#titleparts: Talk:Foo/bar/baz/quok | -1 }}Talk:Foo/bar/baz Strips one segment from the end of the string. 参见{{BASEPAGENAME}}。
{{#titleparts: Talk:Foo/bar/baz/quok | -4 }} Strips all 4 segments from the end of the string
{{#titleparts: Talk:Foo/bar/baz/quok | -5 }} Strips 5 segments from the end of the string (more than exist)
{{#titleparts: Talk:Foo/bar/baz/quok | | -1 }} quok Returns last segment. 参见{{SUBPAGENAME}}。
{{#titleparts: Talk:Foo/bar/baz/quok | -1 | 2 }} bar/baz Strips one segment from the end of the string, then returns the second segment and beyond
{{#titleparts: Talk:Foo/bar/baz/quok | -1 | -2 }} baz Start copying at the second last element; strip one segment from the end of the string

Before processing, the pagename parameter is HTML-decoded: if it contains some standard HTML character entities, they will be converted to plain characters (internally encoded with UTF-8, i.e. the same encoding as in the MediaWiki source page using this parser function).

For example, any occurrence of &quot;, &#34;, or &#x22; in pagename will be replaced by ".
No other conversion from HTML to plain text is performed, so HTML tags are left intact at this initial step even if they are invalid in page titles.

Some magic keywords or parser functions of MediaWiki (such as {{PAGENAME }} and similar) are known to return strings that are needlessly HTML-encoded, even if their own input parameter was not HTML-encoded:

The titleparts parser function can then be used as a workaround, to convert these returned strings so that they can be processed correctly by some other parser functions also taking a page name in parameter (such as {{PAGESINCAT: }} but which are still not working properly with HTML-encoded input strings.

For example, if the current page is Category:Côte-d'Or, then:

  • {{#ifeq: {{FULLPAGENAME}} | Category:Côte-d'Or | 1 | 0 }}, and {{#ifeq: {{FULLPAGENAME}} | Category:Côte-d&apos;Or | 1 | 0 }} are both returning 1; (the #ifeq parser function does perform the HTML-decoding of its input parameters).
  • {{#switch: {{FULLPAGENAME}} | Category:Côte-d'Or = 1 | #default = 0 }}, and {{#switch: {{FULLPAGENAME}} | Category:Côte-d&apos;Or = 1 | #default = 0 }} are both returning 1; (the #switch parser function does perform the HTML-decoding of its input parameters).
  • {{#ifexist: {{FULLPAGENAME}} | 1 | 0 }}, {{#ifexist: Category:Côte-d'Or | 1 | 0 }}, or even {{#ifexist: Category:Côte-d&apos;Or | 1 | 0 }} will all return 1 if that category page exists (the #ifexist parser function does perform the HTML-decoding of its input parameters);
  • {{PAGESINCAT: Côte-d'Or }} will return a non-zero number, if that category contains pages or subcategories, but:
  • {{PAGESINCAT: {{CURRENTPAGENAME}} }}, may still unconditionally return 0, just like:
  • {{PAGESINCAT: {{PAGENAME|Category:Côte-d'Or}} }}
  • {{PAGESINCAT: {{PAGENAME|Category:Côte-d&apos;Or}} }}

The reason of this unexpected behavior is that, with the current versions of MediaWiki, there are two caveats:

  • {{FULLPAGENAME}}, or even {{FULLPAGENAME|Côte-d'Or}} may return the actually HTML-encoded string Category:Côte-d&apos;Or and not the expected Category:Côte-d'Or, and that:
  • {{PAGESINCAT: Côte-d&apos;Or }} unconditionally returns 0 (the PAGESINCAT magic keyword does not perform any HTML-decoding of its input parameter).

The simple workaround using titleparts (which will continue to work if the two caveats are fixed in a later version of MediaWiki) is:

  • {{PAGESINCAT: {{#titleparts: {{CURRENTPAGENAME}} }} }}
  • {{PAGESINCAT: {{#titleparts: {{PAGENAME|Category:Côte-d'Or}} }} }}
  • {{PAGESINCAT: {{#titleparts: {{PAGENAME|Category:Côte-d&apos;Or}} }} }}, that all return the actual number of pages in the same category.

Then the decoded pagename is canonicalized into a standard page title supported by MediaWiki, as much as possible:

  1. All underscores are automatically replaced with spaces:
    {{#titleparts: Talk:Foo/bah_boo|1|2}}bah boo Not bah_boo, despite the underscore in the original.
  2. The string is split a maximum of 25 times; further slashes are ignored and the 25th element will contain the rest of the string. The string is also limited to 255 characters, as it is treated as a page title:
    {{#titleparts: a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/aa/bb/cc/dd/ee | 1 | 25 }}y/z/aa/bb/cc/dd/ee
    If for whatever reason you needed to push this function to its limit, although very unlikely, it is possible to bypass the 25 split limit by nesting function calls:
    {{#titleparts: {{#titleparts: a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/aa/bb/cc/dd/ee| 1 | 25 }} | 1 | 2}}z
  3. Finally the first substring is capitalized according to the capitalization settings of the local wiki (if that substring also starts by a local namespace name, that namespace name is also normalized).
    {{#titleparts: talk:a/b/c }}Talk:A/b/c
警告 警告:

You can use #titleparts as a small "string parser and converter", but consider that it returns the first substring capitalized:

{{#titleparts: one/two/three/four|1|1 }}One
{{#titleparts: one/two/three/four|1|2 }}two

If lower case is needed, use lc: function to control output:

{{lc: {{#titleparts: one/two/three/four|1|1 }} }}one

You can prepend a 'dummy' slash at the beginning of the string to get the correct first substring capitalization (uppercase or lowercase). Use 2 instead of 1 for first segment to return:

{{#titleparts: /one/two/three/four|1|2 }}one
{{#titleparts: /One/two/three/four|1|2 }}One
警告 警告:

Certain characters that are illegal in a page title will cause #titleparts to not parse the string:

{{#titleparts: {one/two} | 1 | 1 }}{one/two}. Does not produce the expected: {one
{{#titleparts: [[page]]/123 | 1 | 2 }}page/123. Does not work because brackets are illegal in page titles and this parser function does not process links embedded in its input pagename parameter, even when they use the MediaWiki syntax, or any other HTML or MediaWiki tags.
{{#titleparts: red/#00FF00/blue | 1 | 3 }} → "". Does not work because "#" is also illegal in page titles.
警告 警告:

If any part of the title is just "." or "..", #titleparts will not parse the string:

{{#titleparts: one/./three | 1 | 1 }}one/./three. The whole string is returned. It does not produce the expected: one
警告 警告: This function does not degrade gracefully if the input exceeds 255 bytes in UTF-8. If the input string is 256 bytes or more, the whole string is returned.

StringFunctions

All of these functions (len, pos, rpos, sub, replace, explode) are integrated from the StringFunctions extension, but are only available if an administrator sets $wgPFEnableStringFunctions = true; in LocalSettings.php.

All of these functions operate in O(n) time complexity, making them safe against DoS attacks.

  1. Some parameters of these functions are limited through global settings to prevent abuse.
See section Limits hereafter.
  1. For functions that are case sensitive, you may use the magic word {{lc:string}} as a workaround in some cases.
  1. To determine whether a MediaWiki server enables these functions, check the list of supported Extended parser functions in Special:Version.
  1. String length is limited by $wgPFStringLengthLimit variable, default to 1000.

#len

The #len parser function was merged from the StringFunctions extension as of version 1.2.0.

The #len function returns the length of the given string. The syntax is:

{{#len:string}}

The return value is always a number of characters in the source string (after expansions of template invocations, but before conversion to HTML). If no string is specified, the return value is zero.

  • This function is safe with UTF-8 multibyte characters.
Example:
    • {{#len:Žmržlina}}8
  • Leading and trailing spaces or newlines are not counted, but intermediate spaces and newlines are taken into account.
Examples:
    • {{#len:Icecream }}8
    • {{#len: a   b }}5 - 3 spaces between 2 characters
  • Characters given by reference are not converted, but counted according to their source form.
    • {{#len:&nbsp;}}6 - named characters references
    • {{#len:&#32;}}5 - numeric characters references, not ignored despite it designates a space here.
  • Tags such as <nowiki> and other tag extensions will always have a length of zero, since their content is hidden from the parser.
Example:
    • {{#len:<nowiki>This is a </nowiki>test}}4

#pos

The #pos parser function was merged from the StringFunctions extension as of version 1.2.0.

The #pos function returns the position of a given search term within the string. The syntax is:

{{#pos:string|search term|offset}}

The offset parameter, if specified, tells a starting position where this function should begin searching.

If the search term is found, the return value is a zero-based integer of the first position within the string.

If the search term is not found, the function returns an empty string.

  • This function is case sensitive.
  • This function is safe with UTF-8 multibyte characters.
Example: {{#pos:Žmržlina|žlina}} returns 3.
  • As with #len, <nowiki> and other tag extensions are treated as having a length of 1 for the purposes of character position.
Example: {{#pos:<nowiki>This is a </nowiki>test|test}} returns 1.

#rpos

The #rpos parser function was merged from the StringFunctions extension as of version 1.2.0.

The #rpos function returns the last position of a given search term within the string. The syntax is:

 {{#rpos:string|search term}}

If the search term is found, the return value is a zero-based integer of its last position within the string.

If the search term is not found, the function returns -1.

When using this to search for the last delimiter, add +1 to the result to retrieve position after the last delimiter. This also works when the delimiter is not found, because "-1 + 1" is zero, which is the beginning of the given value.

  • This function is case sensitive.
  • This function is safe with UTF-8 multibyte characters.
Example: {{#rpos:Žmržlina|lina}} returns 4.
  • As with #len, <nowiki> and other tag extensions are treated as having a length of 1 for the purposes of character position.
Example: {{#rpos:<nowiki>This is a </nowiki>test|test}} returns 1.

#sub

The #sub parser function was merged from the StringFunctions extension as of version 1.2.0.

The #sub function returns a substring from the given string. The syntax is:

{{#sub:string|start|length}}

The start parameter, if positive (or zero), specifies a zero-based index of the first character to be returned.

Example: {{#sub:Icecream|3}} returns cream.

{{#sub:Icecream|0|3}} returns Ice.

If the start parameter is negative, it specifies how many characters from the end should be returned.

Example: {{#sub:Icecream|-3}} returns eam.

The length parameter, if present and positive, specifies the maximum length of the returned string.

Example: {{#sub:Icecream|3|3}} returns cre.

If the length parameter is negative, it specifies how many characters will be omitted from the end of the string.

Example: {{#sub:Icecream|3|-3}} returns cr.

If the start parameter is negative, it specifies how many characters from the end should be returned. The length parameter, if present and positive, specifies the maximum length of the returned string from the starting point.

Example: {{#sub:Icecream|-3|2}} returns ea.

  • If the length parameter is zero, it is not used for truncation at all.
    • Example: {{#sub:Icecream|3|0}} returns cream. {{#sub:Icecream|0|3}} returns Ice.
  • If start denotes a position beyond the truncation from the end by negative length parameter, an empty string will be returned.
    • Example: {{#sub:Icecream|3|-6}} returns an empty string.
  • This function is safe with UTF-8 multibyte characters.
Example: {{#sub:Žmržlina|3}} returns žlina.
  • As with #len, <nowiki> and other tag extensions are treated as having a length of 1 for the purposes of character position.
Example: {{#sub:<nowiki>This is a </nowiki>test|1}} returns test.

#replace

The #replace parser function was merged from the StringFunctions extension as of version 1.2.0.

The #replace function returns the given string with all occurrences of a search term replaced with a replacement term.

{{#replace:string|search term|replacement term}}

If the search term is unspecified or empty, a single space will be searched for.

If the replacement term is unspecified or empty, all occurrences of the search term will be removed from the string.

  • This function is case-sensitive.
  • Even if the replacement term is a space, an empty string is used.
This is a side-effect of the MediaWiki parser.

To use a space as the replacement term, put it in nowiki tags.

    • Example: {{#replace:My_little_home_page|_|<nowiki> </nowiki>}} returns My little home page.
    • If this doesn't work, try {{#replace:My_little_home_page|_|<nowiki/> <nowiki/>}} with two self-closing tags.
    • Note that this is the only acceptable use of nowiki in the replacement term, as otherwise nowiki could be used to bypass $wgStringFunctionsLimitReplace, injecting an arbitrarily large number of characters into the output.
For this reason, all occurrences of <nowiki> or any other tag extension within the replacement term are replaced with spaces.
  • This function is safe with UTF-8 multibyte characters.
Example: {{#replace:Žmržlina|ž|z}} returns Žmrzlina.
  • If multiple items in a single text string need to be replaced, one could also consider Extension:ReplaceSet .
It adds a parser function for a sequence of replacements.
Case-insensitive replace

Currently the syntax doesn't provide a switch to toggle case-sensitivity setting. But you may make use of magic words of formatting as a workaround. (e.g. {{lc:your_string_here}}) For example, if you want to remove the word "Category:" from the string regardless of its case, you may type:

{{#replace:{{lc:{{{1}}}}}|category:|}}

But the disadvantage is that the output will become all lower-case. If you want to keep the casing after replacement, you have to use multiple nesting levels (i.e. multiple replace calls) to achieve the same thing.

#explode

The #explode parser function was merged from the StringFunctions extension as of version 1.2.0.

The #explode function splits the given string into pieces and then returns one of the pieces. The syntax is:

{{#explode:string|delimiter|position|limit}}

The delimiter parameter specifies a string to be used to divide the string into pieces. This delimiter string is then not part of any piece, and when two delimiter strings are next to each other, they create an empty piece between them. If this parameter is not specified, a single space is used. The limit parameter is available in ParserFunctions only, not the standalone StringFunctions version, and allows you to limit the number of parts returned, with all remaining text included in the final part.

The position parameter specifies which piece is to be returned. Pieces are counted from 0. If this parameter is not specified, the first piece is used (piece with number 0). When a negative value is used as position, the pieces are counted from the end. In this case, piece number -1 means the last piece. Examples:

  • {{#explode:And if you tolerate this| |2}} returns you
  • {{#explode:String/Functions/Code|/|-1}} returns Code
  • {{#explode:Split%By%Percentage%Signs|%|2}} returns Percentage
  • {{#explode:And if you tolerate this| |2|3}} returns you tolerate this

The return value is the position-th piece. If there are fewer pieces than the position specifies, an empty string is returned.

  • This function is case sensitive.
  • The maximum allowed length of the delimiter is limited through $wgStringFunctionsLimitSearch global setting.
  • This function is safe with UTF-8 multibyte characters. Example: {{#explode:Žmržlina|ž|1}} returns lina.

#urldecode

#urldecode converts the escape characters from an 'URL encoded' string string back to readable text. The syntax is:

{{#urldecode:value}}

Notes:

  • This function works by directly exposing PHP's urldecode() function.
  • A character-code-reference can be found at www.w3schools.com.
  • The opposite, urlencode, has been integrated into MediaWiki as of version 1.18; for examples, see Help:Magic Words .
  • urldecode was merged from Stringfunctions in 2010, by commit 1b75afd18d3695bdb6ffbfccd0e4aec064785363

Limits

This module defines three global settings:

These are used to limit some parameters of some functions to ensure the functions operate in O(n) time complexity, and are therefore safe against DoS attacks.

$wgStringFunctionsLimitSearch

This setting is used by #pos, #rpos, #replace, and #explode. All these functions search for a substring in a larger string while they operate, which can run in O(n*m) and therefore make the software more vulnerable to DoS attacks. By setting this value to a specific small number, the time complexity is decreased to O(n).

This setting limits the maximum allowed length of the string being searched for.

The default value is 30 multibyte characters.

$wgStringFunctionsLimitReplace

This setting is used by #replace. This function replaces all occurrences of one string for another, which can be used to quickly generate very large amounts of data, and therefore makes the software more vulnerable to DoS attacks. This setting limits the maximum allowed length of the replacing string.

The default value is 30 multibyte characters.

一般帮助

替代

Parser functions can be substituted by prefixing the hash character with subst::

{{subst:#ifexist: Help:Extension:ParserFunctions/zh | [[Help:Extension:ParserFunctions/zh]] | Help:Extension:ParserFunctions/zh }}the code [[Help:Extension:ParserFunctions/zh]] will be inserted in the wikitext since the page Help:Extension:ParserFunctions/zh exists.
警告 警告:

The results of substituted parser functions are undefined if the expressions contain unsubstituted volatile code such as variables or other parser functions. For consistent results, all the volatile code in the expression to be evaluated must be substituted. See Help:Substitution.

Substitution does not work within <ref></ref> , you can use {{subst:#tag:ref|}} for this purpose.

重定向

Especially {{#time:…|now-…}} could be handy in redirects to pages including dates, but this does not work.

在表格中逸出的管道符

Parser functions will mangle wikitable syntax and pipe characters (|), treating all the raw pipe characters as parameter dividers. To avoid this, most wikis used a template Template:! with its contents only a raw pipe character (|), since MW 1.24 a {{!}} magic word replaced this kludge. This 'hides' the pipe from the MediaWiki parser, ensuring that it is not considered until after all the templates and variables on a page have been expanded. It will then be interpreted as a table row or column separator. Alternatively, raw HTML table syntax can be used, although this is less intuitive and more error-prone.

You can also escape the pipe character for display as a plain, uninterpreted character using an HTML entity: &#124; .

说明 您输入的 您输出的
Escaping pipe character as table row/column separator
{{!}}
|
Escaping pipe character as a plain character
&#124;
|

剥离空格

Whitespace, including newlines, tabs, and spaces, is stripped from the beginning and end of all the parameters of these parser functions. If this is not desirable, comparison of strings can be done after putting them in quotation marks.

{{#ifeq: foo           |           foo | equal | not equal }}equal
{{#ifeq: "foo          " | "          foo" | equal | not equal }}not equal

To prevent the trimming of then and else parts, see m:Template:If. Some people achieve this by using <nowiki > </nowiki> instead of spaces.

foo{{#if:|| bar }}foofoobarfoo
foo{{#if:||<nowiki /> bar <nowiki />}}foofoo bar foo

However, this method can be used to render a single whitespace character only, since the parser squeezes multiple whitespace characters in a row into one.

<span style="white-space: pre;">foo{{#if:||<nowiki></nowiki>      bar      <nowiki></nowiki>}}foo</span>
foo bar foo

In this example, the white-space: pre style is used to force the whitespace to be preserved by the browser, but even with it the spaces are not shown. This happens because the spaces are stripped by the software, before being sent to the browser.

It is possible to workaround this behavior replacing whitespaces with &#32; (breakable space) or &nbsp; (non-breakable space), since they are not modified by the software:

<span style="white-space: pre;">foo{{#if:||&#32;&#32;&#32;bar&#32;&#32;&#32;}}foo</span>foo bar foo
foo{{#if:||&nbsp;&nbsp;&nbsp;bar&nbsp;&nbsp;&nbsp;}}foofoo   bar   foo

参见

参考资料

  1. 在2011年r86805之前,情況並非如此。
  2. phabricator.wikimedia.org的ParserFunctions.php