R 中的物理常数
只是好奇 - 是否有某个包或数据集包含物理常数的值？我之所以这么问，是因为我现在已经多次错误地输入了 273.15（摄氏度到开尔文转换）。 =)
Just curious - is there a package or dataset somewhere containing values for physical constants? I only ask because I've now typed in 273.15 (Celsius to Kelvin conversion) wrong several times. =)
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收集这些信息是一项相当大的任务，但一些热力学常数在 marelac 中可用：
除了 我对 @joran 引用的问题的回答这些是 NIST 的进一步资源：
http://www.nist.gov/pml/wmd/metric/si- units.cfm
http://www.nist.gov/pml/wmd/pubs/upload/AppC-11-hb44-final.pdf
http://www.nist.gov/pml/wmd/pubs/upload/AppC-11-hb44-final.pdf
我承担了阅读 NIST 常量表的任务，对其进行编辑，以便转换为数字是合理的，这是输入代码：
....这是 dput 版本：
It's a fairly large task to assemble this information but some of the thermodynamic constants are available in marelac:
In addition to the R resources in my answer to the question that that @joran cited these are further resources at NIST:
http://www.nist.gov/pml/wmd/metric/si-units.cfm
http://www.nist.gov/pml/wmd/pubs/upload/AppC-11-hb44-final.pdf
http://www.nist.gov/pml/wmd/pubs/upload/AppC-11-hb44-final.pdf
I took on the task of reading the NIST Constants Table, editing it so the conversion to numeric would be reasonable, and this was the input code:
.... and here is the dput version:
marelac和dielectric封装都有一些物理常数，但不是特别的物理常数。marelac::convert_T将进行温度转换。The packages
marelacanddielectricboth have some physical constants, but not that one in particular.marelac::convert_Twill do the temperature conversions.我可以推荐 2 个选项：
1）如果您一直需要这些常量，您可以使用
C2K<-273.15形式的 .First 库。您可以分配常量并将它们存储在那里。有关详细信息，请参阅 http://cran.r-project。 org/doc/contrib/Lemon-kickstart/kr_first.html2) 如果您只想有时使用这些文件，请以与上述相同的格式将常量保存在文本文件中
x<-273.15然后使用以下格式的 source 函数获取此文件的路径：source(C:\Users\PAth to save file text\formulas.txt)与依赖可能包含也可能不包含所需内容的包相比，这使您可以更好地控制常量。
May I recommend 2 options:
1) If you need these constants all the time you could make use of the .First library in the form of
C2K<-273.15. You can assign constants and store them there. For more on this see http://cran.r-project.org/doc/contrib/Lemon-kickstart/kr_first.html2) If you want to use the files only sometimes save the constants in a text file in the same format as above
x<-273.15and then source the path to this file using the source function in the following format:source(C:\Users\PAth to save file text\formulas.txt)This gives you more control over the constants than relying on a package that may or may not contain what you want.
下载和解析应该相当容易：
http://physicals.nist.gov /cuu/Constants/Table/allascii.txt
[实际上，该文件的格式不好，并且几个常量甚至破坏了近似的固定宽度格式。需要更聪明的处理才能有用]
Should be fairly easy to download and parse this:
http://physics.nist.gov/cuu/Constants/Table/allascii.txt
[actually scratch that, that file is not nicely formatted, and a couple of the constants break even the approximate fixed-width formatting. Needs cleverer processing to be useful]
这是对 NIST CODATA 物理常数表的另一种解析。它与上面 BondedDust 的答案类似，但由于使用了 stringr（我认为），可读性稍微容易一些。
就是这样。现在，可以轻松地在 R 中搜索数据以查找所需的常量，并将要使用的常量分配给变量名称，而无需手动键入它们。
Here is another parsing of the NIST CODATA table of physical constants. It is similar to BondedDust's answer above but with (what I think is) slightly easier readability due to use of
stringr.And that's it. Now it's easy to search — in R — the data to find the constants you want, and assign constants that you will use to variable names, without having to manually type them.
常量包可用。有关用法，请参阅 https://www.r-bloggers .com/2017/07/constants-0-0-1/ 。
例如，您可以像
speed_of_light = with(syms, c0)那样使用它。The constants package is available. For the usage see https://www.r-bloggers.com/2017/07/constants-0-0-1/ .
E.g. you could use it like
speed_of_light = with(syms, c0).