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);

Answer 1

[Jan]

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: ''''';

[Muhammet]

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]

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 ?"