How can i differentiate strings in GUI?

Question

Bugra Alp Nas 2019-3-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/452916-how-can-i-differentiate-strings-in-gui

回答： Walter Roberson 2019-3-27

I've tried so much but I can't find solution. I've wrote something but not working. I'm waiting your advices or easier ways.

My code is:

f_1 = matlabfunction(get(handles.edit1,'string'));
diff(f_1);
set(handles.text3,'string',f_1);

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2019-3-27

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/452916-how-can-i-differentiate-strings-in-gui#answer_367787

You cannot do that. You cannot differentiate character vectors (usefully) or string objects, or function handles.

Given a function handle, you could evaluate it at several locations and use the results to estimate numeric gradient.

Given a character vector, if you have the Symbolic Toolbox, you could potentially use str2sym() to create a symbolic expression that you could then differentiate with diff() . Be sure to specify the variable to differentiate with respect to. You can assign the result to a variable and char() the expression to get something that you can set() as the string property of a uicontrol.

Note: if you have R2017a or earlier, you need to use sym() instead of str2sym() . When you use sym() then the language is not exactly the same as MATLAB and it is not exactly the same as MuPAD either.