What is the purpose of using 2 single quotes ?

Question

Muhammet 2013-7-29

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/83430-what-is-the-purpose-of-using-2-single-quotes

Hi everyone,here is my question that I dont understand why 2 single quotes is used in code below.

set(1,'HandleVisibility','callback');
set(2,'ButtonDownFcn','get(0,''Children'')');
% Note that Children is surrounded by 2 single quotes.

or here :

h=figure;
set(h,’createFcn’,’display(‘’Cloning a figure’’)’);
copyobj(h,0);

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

Jan 2013-7-29

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/83430-what-is-the-purpose-of-using-2-single-quotes#answer_92991

编辑：Jan 2013-7-29

在 MATLAB Online 中打开

Two single quotes create one single quote inside strings. So the following expressions create the same output:

s1 = 'This is called ''string''.'
s2 = ['This is called ', char(39), 'string', char(39), '.']
isequal(s1, s2)  % TRUE

The benefits of the double quotes are obvious, but it gets confusing, when the number of quotes grow:

s3 = 'This is is an empty string: ''''';

2 个评论
显示无隐藏无

Muhammet 2013-7-29

编辑：Muhammet 2013-7-29

Thank you but this is not answer.Because I know form other programmin languages this is kind of escape sequence but for my case not.Because the message shown in command window is : Cloning Figure , not 'Cloning Figure' . You can test it.And also if I try to remove outer quotes it is giving error.

Jan 2013-7-29

编辑：Jan 2013-7-29

In your 2nd example you use accents, not simple quotes. This is not valid in Matlab.

In your original question you do not mention a message at all. Please do not conceal such important information, when you ask a question. Adding this later as comment only wastes your time and the time of your helpers. Thanks.

Now please explain exactly again, what appears where and what you expect instead.

If you want to write a string containing quotes and hide this in callback defined as string, follow the instructions I gave already: While the two quotes appear as single quote, you require 4 quotes to insert two quotes which are displayed as 1 quote. I mentioned already, that this is confusing. Better use function handles instead to avoid such nested quote stuff. Finally I'm still convinced, that my message is an answer to your question: "What is the purpose of using 2 single quotes ?"

请先登录，再进行评论。