Sau đây là danh sách đầy đủ các dữ liệu chuyển đổi đơn vị được sử dụng bởi Mô đun:Convert, although more units may temporarily be at Module:Convert/extra. Trước khi thay đổi trang này, xin hãy thảo luận với cộng đồng tại Thảo luận Mô đun:Convert.
Kịch bản makeunits. rút thông tin từ văn bản wiki của trang này và cho ra mã nguồn Lua thiết lập bảng đơn vị. Bạn có thể chép dán mã nguồn đó vào Mô đun:Convert/data.
The NIST document gives conversion factors correct to 7 places. Factors in bold are exact. If exact factors have more than 7 places, they are rounded and no longer exact. This convert module replaces these rounded figures with the exact figures. For example, the NIST document has 1 square mile = 2.589 988 E+06 square meters. The convert template has 1 square mile = 2,589,988.110336 square meters.
Values for the fundamental physical constants come from the NIST Reference on Constants, Units, and Uncertainty, either the 2010 or the 2014 version. The 2018 version is in preparation. While the articles on the units should be updated as the new versions come out every four years, the few more significant figures provided are probably not necessary for the way this template is used.
“CODATA 2010 Table at NIST”(PDF). From Mohr, Peter J.; Taylor, Barry N.; Newell, David B. (2012). “CODATA recommended values of the fundamental physical constants: 2010”. Reviews of Modern Physics. 84 (4): 1527–1605. doi:10.1103/RevModPhys.84.1527.
“CODATA 2014 Table at NIST”. From Mohr, Peter J.; Newell, David B.; Taylor, Barry N. (2016). “CODATA recommended values of the fundamental physical constants: 2014”. Reviews of Modern Physics. 88 (3). doi:10.1103/RevModPhys.88.035009.
Definitions for additional historical measures are found in sources such as
Fenna, Donald (2002). A Dictionary of Weights, Measures, and Units. Oxford University Press. ISBN978-0-19-107898-9.
In those sections, a level-3 heading (like === Length ===) starts a table that defines units of a certain type. In the subsection, lines that start with | are processed (all other lines, and lines that start with |- or |}, are ignored). A processed line is split into fields (delimited with ||), and leading/trailing whitespace is removed from each field. Empty fields in the Conversions section are given a default value (for example, the plural of yard is formed by adding s, and the US names are also yard and yards).
The second field in each row of the Conversions section normally specifies a unit's symbol, but it can be used for other purposes described in the following. In some cases the text in the second field can be long, and it is convenient to insert colspan="11" | before the text to avoid it wrapping in a narrow column. Any such colspan at the start of the second field is ignored.
Some unit codes are an alias for another spelling of the unit code. For example, the code ft2 is an alias for sqft, and that is indicated by entering =sqft in the Symbol column for the ft2 entry. An alias can only be entered after the primary unit has been defined (the sqft entry must precede the ft2 entry).
Normally there are no other entries on an alias line, however, the following may be used:
default = unit code to specify that the alias has a default output that is different from the primary unit
link = link text to specify that the alias has a link that is different from the primary unit
multiplier = number used as "multiplier = 100" with unit code 100km to define a unit that is 100 times the size of a kilometre
sp=us (or sp = us) to specify that using the alias forces US spelling for that unit
symbol = symbol text to specify that the alias has a symbol that is different from the primary unit
symlink = link text to specify that the alias has a different link when abbreviated ("symbol link")
A unit can be defined as a ratio of two other units. For example, L/km can be defined as "liters per kilometer" by entering ==L/km as the symbol for the unit. A single "=" is used with an alias to specify that a unit code is an alternative name for another unit. By contrast, if "==" is used, the unit code is defined as the first unit "per" the second.
As well as a ratio of two units, a per unit can be of the form "currency per unit". The module recognizes "$" and "£" as currency symbols and shows them appropriately. For example, the input |120|$/acre would be displayed as "$120 per acre", or "$120/acre" if abbreviated.
The definition for a per unit can be followed by the same modifiers available for an alias.
Some unit codes should not be used—if such a code is used, the template displays an error message telling the editor what unit code should be entered. For example, the code feet should not be used, and that is indicated by entering !Message in the Symbol column for the feet entry. There should be no other entries on an error line. The Message text is displayed as an error if feet is used in a conversion. The text should use the special format codes %{ and %} on each side of a unit code. The format codes are replaced with wikitext defined in Module:Convert, and which applies a consistent style to each displayed unit code.
Some units generally use their name, rather than a symbol. That is indicated by inserting ~ before the symbol. For example, the code acre has symbol ~acre which means results will use the singular name "acre", or the plural name "acres", depending on the value.
Some units have a symbol prefixed with *, for example, the symbol given for pitch is *µm. Normally, when units are looked up in the Defaults or Links exception tables, the symbol of the unit is used. However, pitch has a symbol that conflicts with micrometre. The * prefix means that the unit code for pitch is used to look up exceptions, not the symbol.
The prefix column should be empty if SI prefixes are not used, SI for a unit that accepts SI prefixes, SI2 for a unit code that indicates a base unit squared, and SI3 for cubed. For example when defining unit code m2 put SI2 here, and for m3 say SI3. This will scale, for example, km2 to 1000 × 1000 of the base unit, m, or scale mm3 to 0.001 × 0.001 × 0.001 of the base unit m.
The name of the unit is required. The plural name is optional. If no plural name is given, it is created by appending "s" to the singular name. For example, the ft unit has name "foot" and plural name "feet"—the plural name is necessary to avoid the plural of "foot" being "foots".
The US name is optional. If no US name is given, it is the same as the normal name. The US plural name is optional—if it is missing it is created by appending "s" to the US name. When using {{convert}}, the option |sp=us causes the US name to be displayed if a name is required for the convert.
Any %s in the name columns is replaced with the appropriate SI prefix, or is removed if SI prefixes are not appropriate (not suitable for the unit, or not used in the conversion). It is only necessary to use %s if the unit accepts prefixes, and if the prefix is not at the start of the unit's name, for example with m2 and m3.
Spelling exceptions can be handled by entering a row with the exception. For example, see ha which sets the unit name to "hectare"; without that row, the a row would cause ha to have the name "hectoare". There must be an override to document that an exception is intended.
The scale is a value or expression that is used as a factor to convert a value to its corresponding base unit. Commas may be used as a thousand separator (e.g. 1,000,000) or e notation may be used (e.g. 1e6). Fractions should be used when required for exactness (e.g. 1/12).
The Extra column is usually empty, but can contain a value or code when more than a simple Scale is required for a conversion. There are two codes used with fuel efficiency units: volume/length and length/volume. In addition, certain codes are required to indicate that the conversion procedure for the unit is built-in to the module. Any other text is used as an offset in the conversion calculation that occurs with temperature units.
The conversion procedure for some units (for example, the Mach unit of speed) are built into Module:Convert as they are too complex to be specified in a table. That is indicated by entering a code (which must be the same as used in the module) in the Extra column.
The script that reads this page contains a small amount of built-in data that does not conveniently fit into the tables below (see set_builtins in makeunits).
A default is a code for a unit or combination that identifies the output unit or units that will be used if none is specified in the convert template. The Defaults section defines exceptions for unit codes with an SI prefix, where the default output is different from that of the base unit. Also, units using engineering notation may appear in the defaults section to define a default output for the unit.
A default may specify a unit code or an expression that tests the input value, and which produces one of two different outputs depending on that value. In the expression, v represents the input value specified in the convert template, and exclamation marks (!) are used to separate the expression into either three or four fields. For example, the following expression might be used as the default for unit in (inch):
v < 36 ! mm ! cm
The first field is a condition which evaluates to true or false. In this example, if the input value is less than 36, the default output unit is mm; otherwise, it is cm.
If present, the fourth field is appended to the result. For example, the following expression might be used for unit Ml (megalitre):
v < 28.316846592 ! e3 ! e6 ! cuft
If the condition is true, the result is e3cuft; otherwise, it is e6cuft.
A composite input unit consists of two standard units, where the second is a subdivision of the first. For example, |2|ft|6|in may be used to specify 2 feet 6 inches as the input unit in a conversion. See the Input multiples section.
Composites are defined in pairs, but any number of pairs can be used to specify an input. For example, given that ch is defined as a subdivision of mi, and that ft is a subdivision of ch, an input length could be specified as 1|mi|2|ch|3|ft. Also, with suitable pairs defined, an input length could be specified as 4|mi|3|yd|2|ft|1|in. There is no limit to the number of permitted subunits.
A multiple is a unit code that can be used as an output. For example, ftin is a multiple that results in a length being expressed in feet and inches. A multiple may have any number of components defined in the Output multiples section, where each component is a subdivision of the preceding unit.
The link column is the title of the article related to that unit. If the link is preceded with + or *, extra text will be inserted before the link, and the text shown by the link will be adjusted to omit a prefix of "US" or "U.S.", if present. For example, if a unit has the symbol "US gal" (or "U.S. gal"), and if the link is +[[Gallon]], then if the symbol is linked, it would appear as "USgal" ("US" and "gal" link to two different articles). If the link is *[[Gallon]], it would appear as "U.S.gal".
Similarly, if the link is preceded with @, extra text will be inserted before the link, and the text shown by the link will be adjusted to omit a prefix of "imp" or "imperial", if present. For example, if a unit has the symbol "imp gal", and if the link is @[[Gallon]], then if the symbol is linked, it would appear as "impgal" ("imp" and "gal" link two different articles).
The Links section defines exceptions for unit codes with an SI prefix, where the linked article is different from that of the base unit.
Pipe characters (|) in a table need to be encoded. For example, "[[Gallon|gal]]" should be entered as "[[Gallon|gal]]". The script that reads this page replaces each | with |.
Some unit codes match a unit with an SI prefix, and duplicate unit codes are not permitted. For example, Pa can be interpreted as "peta-are" which would prevent the pascal unit of pressure being defined after the are unit of area. However, listing Pa in the Overrides section means that the pascal unit can be defined, in which case peta-are will not be available.
Some unit codes are not intended to be used in a template, but are needed to define exceptions. For example, the code ft has link Foot (unit), but unit psi/ft needs ft to be linked to Fracture gradient. To handle such cases, a unit code starting with "-" is used (-ft-frac for feet with a link to fracture gradient).
If needed, more dashes can be used to define additional exceptions (for example, see -Scwt and --Scwt, which are similar to Scwt but have different names).
In addition to the units defined in the data below, large scale units such as e6km (million kilometres) may be used. The following prefixes may be used, and the linked names are shown if |lk=on:
Any standard unit (not a combination, multiple, or built-in) may be used after an engineering notation prefix, including "temperature change" units, but not "temperature" units.
However, some topics use traditional units that conflict with the above convention. To handle these, Module:Convert/makeunits includes a specials table that adds an "alttype" (alternate type) field to certain whitelisted units. The alttype field allows conversion between units of different type, provided each unit is whitelisted to allow the conversion.
As at December 2013, the following energy units have alttype = "torque" (the first line consists of different units, while the second line consists of aliases for units in the first line):
The following tables define composite input units consisting of multiple unit codes. A composite must consist of two unit codes where the second is a subdivision of the first. In addition, a default output must be specified. Optionally, an alternate unit code or name can be specified. An alternate unit must have the same scale as that of the subdivision, but may have a different name or symbol.
If both an alternate unit and name are provided, the unit will be used when the input consists of only two components, and the alternate name will be used with three or more (generally, the alternate name would be shorter than the unit's standard name or symbol, and that may be desirable when three or more units make up an input composite).
If an alternate name is used, it replaces the unit's symbol and name and plural name. In other words, the same alternate name applies regardless of whether the unit is abbreviated, and regardless of the number of units.
If the unit yd allows ft as a subdivision, and ft allows in, then the input to a conversion can use all three units (for example, {{convert|1|yd|2|ft|3|in}} which specifies the input as 1 yard, 2 feet, 3 inches). There is no limit to the number of units that can be used in an input multiple.
To simplify processing by the script which extracts data from this wikitext, a unit code is required in the first column; that unit code is not used. This section is read after all units and combinations are defined, so the unit codes may refer to items defined anywhere on this page.
The following tables define the "multiple" unit codes that can be used for an output unit. Using a multiple code for the output means that the conversion result contains multiple components (for example, a length expressed in yards, feet, inches).
The following tables list predefined "combination" unit codes that can be used for an output unit. Using a combination code for the output means that the input value is converted to more than one unit. In addition to the combinations listed here, units may be combined by separating unit codes with a space or plus character.
The following tables define default outputs for unit codes that use an SI prefix or an engineering notation prefix, where the default output is different from that of the base unit.
The following table defines equivalent unit types for some of the types that can be generated automatically for unit codes of the form x/y (x per y). For example, the unit code kg/hl is not defined, so if it were used, it would be regarded as kilograms per hectolitre with unit type mass/volume; the following table would translate that to density so the unit could be converted with other density units. If "Density" is specified in the Link column, the unit name or symbol would be linked to Density if |lk=on is used.
In addition, a scale multiplier can be specified; that allows mass/area units to be converted to pressure units on the assumption that the mass refers to the force due to the "weight" of an object.
The following tables define "override" unit codes which conflict with another unit when it is combined with one of the SI prefixes. The script which processes this page rejects unit codes that duplicate a known entry, however, that checking is not performed for the unit codes listed here. The Comment field documents the conflict, but is otherwise ignored.
