How to concatenate a string in regexprep to include a variable and a string as the regular expression

13 次查看（过去 30 天）

Thomas Dixon 2019-11-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/493107-how-to-concatenate-a-string-in-regexprep-to-include-a-variable-and-a-string-as-the-regular-expressio

评论： Thomas Dixon 2019-11-26

Matlab script.txt

I am trying to do a number of things in regexprep. I solve a number of cascading differential equations and then I want to quickly write them in latex. This will undoubtebly get bigger and so good programming is requried, hence why I pass the buck on....

I first want to read in the file and decide which 'order' of differnetial equations I want to computer. In this example I pick order 5 and so it goes that order differential equation in the file and strips the differential eqaution by the square brackets.

Then I want to return A5(1) to be A_{\mathrm{i}} in a text file BUT if it were the fourth order I wanted to do I would want A4(1) to be A_{\mathrm{i}} and so I want to concatenate ['A',nstr,'(1)'] to be A_{\mathrm{i}} where nstr is the nth string of the differential equation order.

I then want to also replace the kps string with k_{\mathrm{p+s}} but I can't get the plus sign to work out at all. I believe this is because plus is some kind of operator even though I stick it in the string. I have tried using '\d+', '\+' and it did not work. I still get some funny business.

Here is my MW (my code) you will need to locate the attached Matlab script.txt file on your own PC. help is much appreciated.

input = fileread('........\Matlab script.txt')
n=5
nstr = num2str(n)
input_str = extractBetween(input,['@(x,A',nstr',')['],']');
    Multiplication_delete = regexprep(input_str,'*','');
    ConjAmpswap = strrep(Multiplication_delete,{['conj(A',nstr,'(1))'],['conj(A',nstr,'(2))'],['conj(A',nstr,'(3))'],['conj(A',nstr,'(4))'],['conj(A',nstr,'(5))'],['conj(A',nstr,'(6))'],['conj(A',nstr,'(7))'],['conj(A',nstr,'(8))'],['conj(A',nstr,'(9))'],['conj(A',nstr,'(10))'],['conj(A',nstr,'(11))'],['conj(A',nstr,'(12))'],['conj(A',nstr,'(13))'],['conj(A',nstr,'(14))'],['conj(A',nstr,'(15))']},{'A_{\\mathrm{i}}^*','A_{\\mathrm{s}}^*','A_{\\mathrm{p}}^*','A_{\\mathrm{p\+i}}^*','A_{\\mathrm{p\+s}}^*','A_{\\mathrm{2p}}^*','A_{\\mathrm{2p\+i}}^*','A_{\\mathrm{2p\+s}}^*','A_{\\mathrm{3p}}^*','A_{\\mathrm{3p\+i}}^*','A_{\\mathrm{3p\+s}}^*','A_{\\mathrm{4p}}^*','A_{\\mathrm{4p\+i}}^*','A_{\\mathrm{4p\+s}}^*','A_{\\mathrm{5p}}^*'}); 
    Ampswap = regexprep(ConjAmpswap,{['A',nstr,'(1)'],['A',nstr,'(2)'],['A',nstr,'(3)'],['A',nstr,'(4)'],['A',nstr,'(5)'],['A',nstr,'(6)'],['A',nstr,'(7)'],['A',nstr,'(8)'],['A',nstr,'(9)'],['A',nstr,'(10)'],['A',nstr,'(11)'],['A',nstr,'(12)'],['A',nstr,'(13)'],['A',nstr,'(14)'],['A',nstr,'(15)']},{'A_{\\mathrm{i}}','A_{\\mathrm{s}}','A_{\\mathrm{p}}','A_{\\mathrm{p\+i}}','A_{\\mathrm{p\+s}}','A_{\\mathrm{2p}}','A_{\\mathrm{2p\+i}}','A_{\\mathrm{2p\+s}}','A_{\\mathrm{3p}}','A_{\\mathrm{3p\+i}}','A_{\\mathrm{3p\+s}}','A_{\\mathrm{4p}}','A_{\\mathrm{4p\+i}}','A_{\\mathrm{4p\+s}}','A_{\\mathrm{5p}}'});
    kswap  = regexprep(Ampswap,{'ki','ks','kp','kpi','kps','k2p','k2pi','k2ps','k3p','k3pi','k3ps','k4p','k4pi','k4ps','k5p'},{'k_{\\mathrm{i}}','k_{\\mathrm{s}}','k_{\\mathrm{p}}','k_{\\mathrm{p\+i}}','k_{\\mathrm{p\+s}}','k_{\\mathrm{2p}}','k_{\\mathrm{2p\+i}}','k_{\\mathrm{2p\+s}}','k_{\\mathrm{3p}}','k_{\\mathrm{3p\+i}}','k_{\\mathrm{3p\+s}}','k_{\\mathrm{4p}}','k_{\\mathrm{4p\+i}}','k_{\\mathrm{4p\+s}}','k_{\\mathrm{5p}}'});
    exponentopen = regexprep(kswap,{'exp('},{'e^{'});
    exponentclose = regexprep(exponentopen,{'x)'},{'x}'});
    beta_factor = regexprep(exponentclose,{'(maxBeta/2)'},{'\\Big(\\dfrac{\\beta}{2}\\Big)'});
    i_replace = regexprep(beta_factor,{'1i'},{'i'});

10 个评论
显示 8更早的评论隐藏 8更早的评论

Thomas Dixon 2019-11-26

Thanks again. You have peaked my curisoity now. MATLAB has inbuilt functionaly whereby I can hover over a paranthases with the cursor and it will tell me where its closed/opened. This suggests it has a way of tracking the functionality for maths purposes (as you would hope). LaTeX on the other hand wants to track the functionality for a visual for example:

exp(i*(k1-k2)*x) is the regular MATLAB expression

e^{i(\mathrm{k_1} - \mathrm{k_2})x} is the LaTeX formalism.

But even as i type this into the editor for this questions page I can see that it is tracking both the curly brackets and the parantheses and returning the coresponding closer/openeer.

Do you think it is possible to use this functionality to map the syntax.

For example:

I want to always take the string exp and change it to e^

I then want the next bracket and its corresponding closer to form a set of curly brackets ie. exp(<--.......(...[some more stuff]....)....even more stuff ...(...).....)<-- Will change to e^{...[all the middle stuff]...} where the inner bracketed expressions will be remembered but not included
Then input the inner expressions (or perform regular expression replacements on them) to the curly brackets in the newly set LaTeX form.

Stephen23 2019-11-26

编辑：Stephen23 2019-11-26

在 MATLAB Online 中打开

Perhaps something like this:

>> C = {'','\+i','\+s'};
>> F = @(n)sprintf('%dp%s',fix(n/3),C{1+mod(n,3)});
>> G = @(s)regexprep(F(sscanf(s,'%d')),{'^0p','^\\\+'},'');
>> rgx = sprintf('A%d%s',4,'\((\d+)\)'); % specify the "n" value here
>> rpl = 'A_\{\\mathrm\{${G($1)}\}\}';
>> regexprep('hello A4(1) world',rgx,rpl)
ans =
hello A_{\mathrm{i}} world
>> regexprep('hello A4(2) world',rgx,rpl)
ans =
hello A_{\mathrm{s}} world
>> regexprep('hello A4(3) world',rgx,rpl)
ans =
hello A_{\mathrm{1p}} world
>> regexprep('hello A4(4) world',rgx,rpl)
ans =
hello A_{\mathrm{1p\+i}} world
>> regexprep('hello A4(5) world',rgx,rpl)
ans =
hello A_{\mathrm{1p\+s}} world
>> regexprep('hello A4(6) world',rgx,rpl)
ans =
hello A_{\mathrm{2p}} world
>> regexprep('hello A4(7) world',rgx,rpl)
ans =
hello A_{\mathrm{2p\+i}} world

You might like to download my FEX submission:

https://www.mathworks.com/matlabcentral/fileexchange/48930-interactive-regular-expression-tool

it lets you quickly try regular expressions and see regexp's outputs as you type.

Thomas Dixon 2019-11-26

HAHAHA. This is exactly the reason that you're in the A side of Q&A's. This is a ridculusly elegant solution compared to the hash I was making myself.

Well played sir!

请先登录，再进行评论。

请先登录，再回答此问题。