Fixing Matlab Plot Error: Invalid Color/Linetype Argument

[MathematicalPhysicist]

I am using Matlab's 2017Rb academic license.

And while trying to operate the following sequence of commands:

x = linspace(0,2*pi,1000);
y = sin(2*x);
plot(x,y,'k−','linew',2); hold on;

I get the following warning:

Error using plot
Error in color/linetype argument.

What seems to be wrong in the above code?

Thanks.

 

[jedishrfu]

Check this Matlab plot command page. The examples show some args:

https://www.mathworks.com/help/matlab/ref/plot.html?requestedDomain=www.mathworks.com

 

[MathematicalPhysicist]

So the error is in 'k-', how it should be?
'-k', yes now it works.

 

[AgusCF]

So the error is in 'k-', how it should be?
'-k', yes now it works.

But... '-k' make the same as 'k' I think...

 

[FactChecker]

So the error is in 'k-', how it should be?
'-k', yes now it works.

Interesting. The documentation says that the order of the symbols doesn't matter. So this is either a bug or there is something else going on.

 

[MathematicalPhysicist]

Interesting. The documentation says that the order of the symbols doesn't matter. So this is either a bug or there is something else going on.

Did you try it in your machine?

I have Ubuntu 16.04 as the OS in this computer.

 

[MathematicalPhysicist]

But... '-k' make the same as 'k' I think...

Yes, it works as well.

 

[AgusCF]

Yes, it works as well.

And... Why were you trying to plot 'k-'?

 

[MathematicalPhysicist]

And... Why were you trying to plot 'k-'?

I copy-paste this snippet of code from some lecture notes I am reading.

So there I had this 'k-'.

 

[FactChecker]

Did you try it in your machine?

I have Ubuntu 16.04 as the OS in this computer.

I'm retired and no longer have access to MATLAB. I'm thinking about buying it just for these occasions.

 

[Image Analyst]

It's not a bug. And the order doesn't matter. The problem is you don't have a dash in there. It's some character that looks like a dash but isn't. When I paste in your code it shows the error message

Error using plot
Error in color/linetype argument.
Error in test1 (line 3)
plot(x,y,'k?','linew',2); See the question mark indicating it doesn't know what that character is? If you get rid of that "dash" and replace it with a real dash (minus sign), it will work perfectly fine.

 

[FactChecker]

It's not a bug. And the order doesn't matter. The problem is you don't have a dash in there. It's some character that looks like a dash but isn't. When I paste in your code it shows the error message

Error using plot
Error in color/linetype argument.
Error in test1 (line 3)
plot(x,y,'k?','linew',2);See the question mark indicating it doesn't know what that character is? If you get rid of that "dash" and replace it with a real dash (minus sign), it will work perfectly fine.

Good catch! This is one of the frustrating things about copying and pasting text -- they can have characters and do other things you don't want. I like to paste into a programmer editor that I can control, like vim, just to be sure that the text is exactly what I wanted. I often have to replace things that I don't want in code. Then I copy the vim text and paste that into the target code.