Matlab中使用regexp的递归技巧 [英] Recursive tricks with regexp in Matlab

问题描述

我试图用regexprep解决问题-给了我一个代表函数的字符串；它包含如下模式:'sin(arcsin(f))'其中f-任何子字符串；我需要用简单的'f_2'替换它.除非遇到这样的字符串，否则我会成功使用regexprep:

I tried to use regexprep to solve a problem - I'm given a string, that represents a function; it contains a patterns like these: 'sin(arcsin(f))' where f - any substring; and I need to replace it with simple 'f_2'. I successfully used regexprep unless I face with such string:

str = 'sin(arcsin(sin(arcsin(f_2))))*x^2';
str = regexprep(str, 'sin\(arcsin\((\w*)\)\)','$1');

它返回

str =

sin(arcsin(f_2))*x^2

但是我希望它成为

str =

f_2*x^2

有什么办法可以解决(除了明显的for循环解决方案).

Is there any way to solve it (except obvious solution with for-loops).

推荐答案

我无法对此进行测试，但是我认为我找到了一个表达式，可以多次调用该表达式以完成您所要求的操作；每次它将从方程式中剥离"一对sin(arcsin())对.一旦停止更改，就完成了.

I was not able to test this, but I thinkg I found an expression that you can call multiple times to do what you asked for; each time it will "strip" one sin(arcsin()) pair out of your equation. Once it stops changing, you're done.

(.*)sin\(arcsin\((.*(\(.*?\))*)(\)\).*$)

以下是一些Matlab代码，展示了其工作方式:

Here is some Matlab code that shows how this might work:

str = 'sin(arcsin(sin(arcsin(f_2))))*x^2';
regex = (.*)sin\(arcsin\((.*(\(.*?\))*)(\)\).*$);

oldlength = 0
newlength = length(str)

while (newlength != oldlength)
  oldlength = newlength;
  str = regexprep(str, regex,'$1$2');
  newlength = length(str);
end

正如我所说-我无法测试.让我知道您是否对此有任何疑问.

As I said - I could not test this. Let me know if you have any problems with this.

正则表达式的演示

http://regex101.com/r/bR9gC7

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