Template talk:Convert

Rounding for multiple units

I want to have an input of 1991 cc display as 2.0 L (1991 cc; 121 cu in) - ie L to 1 digit and cc and cuin to 0 digits. I was hoping that something like {{cvt|1991|cc|L cc cuin|order=out|adj=ri1|0}} would do it, based on |abbr=in abbreviating the first displayed param rather than the actual first. But it rounds the actual first param and shows as 2 L (1,991.0 cc; 121 cu in). Any clues?  Stepho  talk  09:42, 12 February 2023 (UTC)

Have you considered using {{Convert}} twice? (§ doc) DePiep (talk) 09:49, 12 February 2023 (UTC)

I did. It's my fall-back but it's kind of clumsy and I was hoping for something shorter and more elegant. And anything complex is harder for future (possibly novice) editors to replicate for new bits of info they want to add.  Stepho  talk  11:06, 12 February 2023 (UTC)

Yes. I did not research deeply, so maybe that more elegant solution exists. DePiep (talk) 11:55, 12 February 2023 (UTC)

I have been banging my head against this wall for a long time. In general, I just omit cubic inches since they are largely disused, even in the US. A better workaround is {{cvt|1.991|L|cc cuin|adj=ri1|0}} which produces:

• 2.0 L (1,991 cc; 121 cu in). Best,  Mr.choppers | ✎  13:35, 15 February 2023 (UTC)

Yes, that looks like a good work-around. Thanks.  Stepho  talk  21:45, 15 February 2023 (UTC)

Hundredweight

For Adler (locomotive), how does one convert 177 hundredweight (long) to pounds and kilograms? Peter Horn User talk 21:37, 10 March 2023 (UTC)

{{convert|177|Lcwt|lbs kg}} should do the trick: 177 long hundredweight (19,800 lb; 9,000 kg). XAM2175 ^(T) 21:58, 10 March 2023 (UTC)

@XAM2175: Thanks Peter Horn User talk 01:35, 11 March 2023 (UTC)

Special adjective

Most of the articles I write are related to 19th century military history, when cannon were generally known by the weight of the projectile they fired, so the general names for these guns are often things like 32-pounder, 12-pounder, 100-pounder, etc. Is there a way to make this template spit out the -pounder adjective, or will I just need to manually perform conversions of these weights into kilograms? Hog Farm _Talk 02:56, 15 March 2023 (UTC)

How about an example of what you would like displayed in an article? Help:Convert#Extra words shows some suggestions but convert shows the name of the unit so it will show "pound" which would look silly next to "pounder". If you explain what is wanted, we may have some ideas. Don't perform manual calculations. How many articles (roughly: 10? 1000?). Johnuniq (talk) 03:58, 15 March 2023 (UTC)

An example would be in the text at Battle of Grand Gulf - This fort mounted a 100-pounder Blakely rifle, another 8-inch Dahlgren piece, and two more 32-pounders., with pounds to kg for the gun sizes, or USS Marmora (1862) - Initially, Marmora was armed with two 12-pounder rifled cannons and two 24-pounder guns. (a change I've specifically been asked to make at the FAC). I'm unclear how many articles this could potentially be used in, but see Caliber#Pounds as a measure of cannon bore for a better explanation of the situation. Hog Farm _Talk 13:34, 15 March 2023 (UTC)

How about {{convert|100|lb|kg|disp=x|er (|)|0|sing=on}} to give "The fort mounted a 100-pounder (45 kg) Blakely rifle."

And {{convert|32|lb|kg|disp=x|ers (|)|0|sing=on}} to give "two more 32-pounders (15 kg)."  Stepho  talk  13:53, 15 March 2023 (UTC)

This usage will appear in a very large number of milhist articles even in the Cold War era. I've also seen it abbreviated as "pdr", though I'm not sure if that's considered acceptable. The form suggested by @Stepho-wrs seems to satisfy the request, but I wonder if perhaps it would be worth creating a new template employing the Convert module especially for this purpose? XAM2175 ^(T) 13:58, 15 March 2023 (UTC)

I don't think it's appropriate to supply kg conversions for x-pounder guns. Conversions are to help people who are more familiar with the other units in the field under discussion. If there were a tradition of rating guns in terms of kg, then we should give conversions, but there is no such kg tradition, only a pounder tradition. And for most of the guns that are described as x-pounder, there is no object with a mass of x pounds that is used with them. A bore diameter in mm is helpful to readers, but not a conversion to kg. Indefatigable (talk) 16:03, 15 March 2023 (UTC)

I agree with Indefatigable. Stepho's solution is very elegant (still trying to figure out what some of it does exactly), but I do not think there is a reason to convert these to metric as it is not how guns are measured. If anything, these would best be manually converted to cm or whatever unit of length is most suitable.  Mr.choppers | ✎  19:59, 15 March 2023 (UTC)

That's true for the specific case of weights. However, metric units of length are used for the caliber of artillery; even in the US, artillery intended for use in NATO has a metric caliber, e.g., 105 mm, 155 mm. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:17, 16 March 2023 (UTC)

I agree, that's why I suggested manually converting the weight into diameter, if that is even possible. Is there a clear conversion method from, say a 12-pounder to millimeters?  Mr.choppers | ✎  12:41, 16 March 2023 (UTC)

For modern US artillery, there's the millimeter caliber, but in Mexican War/Civil War/etc., the cannon were generally known by either an inch bore-diameter: see, for instance, 3-inch ordnance rifle or M1841 6-pounder field gun. I don't think I've ever seen a source refer to a Civil War cannon by a mm designation. Hog Farm _Talk 14:16, 16 March 2023 (UTC)

I'm not aware of a US metric caliber weapon prior to NATO. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 16:49, 17 March 2023 (UTC)

There's the 105mm M2/M101 to start. Orange Suede Sofa (talk) 18:46, 17 March 2023 (UTC)

They likely did not use mm, but a conversion is in order to explain obsolete units that would otherwise be meaningless to the majority of readers.  Mr.choppers | ✎  20:32, 17 March 2023 (UTC)

They did use mm, as can be seen from the technical manual from the time. Orange Suede Sofa (talk) 20:38, 17 March 2023 (UTC)

We've shown that convert can translate from pounder to kg (although it is a bit long to call it elegant). The question of whether it should be used, in what context and whether it should have a wrapper template is a question that belongs at WP:WEAPON. And of course we can't convert from pounder to mm but the question of converting inches to mm for cannons also belongs there.  Stepho  talk  20:55, 17 March 2023 (UTC)

Li unit

I was editing Heaven and I discovered the measure in the Theravada Buddhism is the lǐ. Is it possible to add it? Thanks.--Carnby (talk) 17:28, 24 March 2023 (UTC)

It seems to me the most appropriate units to support in the Convert template are ones that have a generally agreed value in SI units. The article about the li unit seems to indicate there are a variety of different values. It might be more appropriate to expect any editor who mentions this unit to explain what value is intended in the article where it is used, rather than rely on a conversion template. Jc3s5h (talk) 17:35, 24 March 2023 (UTC)

Well, I'm not sure SI is the touchstone, but in general {convert} should restrict itself to units that have been reasonably stable over time. EEng 20:09, 24 March 2023 (UTC)

If added it then we would have to be able to distinguish between the various values used over time - in much the same way that we distinguish between imperial and US gallons. Possibly we could have the units called "gongli", "li-xia", "li-qin", etc.  Stepho  talk  01:32, 25 March 2023 (UTC)

Liter

Hi, the template appears to still be outputting "l" for liter, eg. 42 US gallons (160 L; 35 imp gal). Can this be updated to output "L" instead, per the MOS? Thanks. BilCat (talk) 18:14, 25 March 2023 (UTC)

Support this change, for what it's worth. The relevant section of the MOS is roughly half-way through the table at MOS:INCH. XAM2175 ^(T) 21:30, 25 March 2023 (UTC)

Unit USgal has a default output of l impgal. Use L to display uppercase:

• {{convert|42|USgal|L impgal}} → 42 US gallons (160 L; 35 imp gal)

Johnuniq (talk) 23:28, 25 March 2023 (UTC)

@Johnuniq, with respect, the entire point of the requested change is that the use of l rather than L as the symbol for litres is inconsistent with the Manual of Style. Changing the default output accordingly – for all relevant conversions, not just USgal – achieves greater MOS compliance.
I would in fact go further and say that the upper-case symbol should be used even where the lower-case symbol has been specified in the template arguments, but I appreciate that that might be considered too far for the "should not be used" wording found in the MOS. XAM2175 ^(T) 23:53, 25 March 2023 (UTC)

Concur. Yes, I know how to make it display the uppercase, but I shouldn't have to, as the uppercase is recommended, not just optional. BilCat (talk) 00:09, 26 March 2023 (UTC)

So, what is the proposal? That every l be replaced with L for the outputs at Module:Convert/documentation/conversion data? It's messy. Should it be possible to output 12.3 ml? The problem there is that the SI prefixes are determined by software and convert has no provision for sometimes outputting L and sometimes l. A fairly quick fix would be to change all default outputs to use L rather than l. In principle, Module:Convert could be modified to do something special that would work at enwiki and presumably not cause too much disruption at other Wikipedias. However, coding an exception is a lot more complicated than first appears. Johnuniq (talk) 01:57, 26 March 2023 (UTC)

So you're saying the software, as currently written, can't distinguish between an default output for L for liter and ml for mililiter? Well, I guess we'll have to change the MOS again. Can't inconvenience the software for the sake of human rules. BilCat (talk) 04:14, 26 March 2023 (UTC)

Johnuniq mentions the situation "12.3 ml" (SI prefixes), which requires handling different from "7.5 L". MOS is not clear about this a priori. Changing MOS to say so (i.e., outside of {{Convert}} area) would create an enwiki code variant (hard & complicated to code & maintain & internationalise), so we should think before. DePiep (talk) 06:11, 26 March 2023 (UTC)

So basically the answer is, "Screw the MoS, we're not going to try to follow it because it's too difficult, and how dare you try to make more work for me." John should have just said that up front, and I'd have stopped wasting my time here right then. BilCat (talk) 06:35, 26 March 2023 (UTC)

Umm, that's not exactly what was said! If you want an interpretation, please ask. The point is that changing a unit (say from l to L) is simple/fast but it would be tricky/slow to build an exception into the module so ml (or any other SI prefix) can be lowercase (but not must be), while a single l must be converted to L. I'm trying to clarify what the proposal is. Given that it would change a lot of the existing outputs, I suspect it might be worth having a wider discussion. Hey EEng, you probably recall the MOS discussion. Do you have a feeling for what the mood is? Should convert make it not possible to output l but make it possible to output ml? Johnuniq (talk) 07:39, 26 March 2023 (UTC)

If I strike out your unhelpful talk BilCat (pls do so yourself next time), you are supposed to point/quote the MOS lines that say so. I read: "should not be used" and "may use": not prescriptive. (Incidentally, don't see why ENGVAR is mentioned in this). DePiep (talk) 08:20, 26 March 2023 (UTC)

The fact that ml v. mL is an ENGVAR issue is news to me. Personally I would prefer to switch all uses to the upper-case variant, especially if that is a more-simple change to make, but Johnuniq is correct to note that that would probably require a wider discussion. XAM2175 ^(T) 11:22, 26 March 2023 (UTC)

Convert Fractional Inches to Decimal Inches and Centimeters

I recently contributed a large table of lengths corresponding to shoe sizes measured with the Brannock device to Shoe_size#Brannock_Device. All the calculations behind the table values are in inches. Hopwever, one column in particular, of arch lengths, uses a gradation in fiftieths of an inch. That produces some lengths, like 5+69/100, that aren't very intuitive, even for those familiar with more common fractions, like quarters, eighths, and sixteenths.

Can convert be used to display inch lengths in decimal inches, as well as centimeters? kemitchell (talk) 04:49, 26 March 2023 (UTC)

Slightly clumsy but {{convert|{{#expr:5+29/50}}|in|0}} displays 5.58 inches (142 mm)  Stepho  talk  05:00, 26 March 2023 (UTC)

I have no idea what would be best for that article but in general, if the value in the source is 5+69/100 then it might be best to use that in convert and have it display the unusual fraction. If using Stepho's workaround, you might need to add |adj=ri2 to round the display of the input value. That uses the full precision of the calculation for convert (to get the correct output), but rounds the input to two decimal places. Johnuniq (talk) 07:50, 26 March 2023 (UTC)

incorrect use of "change"

The use of this template produces incorrect use of the word "change", for example in the James A. Garfield article. --Espoo (talk) 09:47, 26 March 2023 (UTC)

It seems like the long name always has "change" as part of the displayed unit name. But using the abbreviated unit names on both sides (ie change |abbr=out to |abbr=on) solves it: {{convert|20|F-change|C-change|abbr=on}} gives 20 °F (11 °C)  Stepho  talk  10:01, 26 March 2023 (UTC)

Well it doesn't solve the problem, but thanks for the workaround! --Espoo (talk) 11:39, 26 March 2023 (UTC)