Error with print(): “Output argument ”varargout“ (and maybe others) not assigned”

问题

I have been trying to write a simple script in MATLAB that plots an image, asks to user if they want to print it to a file, and (if yes) does this. However, I have met a strange error with the print() function. Here is my code:

plot(X, Y, 'red');

choice = input('Do you want to print to file this 2D image ? [y/n] ', 'y');

if(choice=='Y' || choice=='y')
{
    print(hFig, '-dpng', strcat(filename, '.png'));
}

If running, it stops inside the if statement with the error:

Error in ==> print at 161 err.message='';

??? Output argument "varargout" (and maybe others) not assigned during call to "C:\Programmi\MATLAB\R2010a\toolbox\matlab\graphics\print.m>print".

Error in ==> istogramma at 30 print(hFig, '-dpng', strcat(filename, '.png'));

Why am I getting this error and how can I avoid this?

回答1:

Your if code with { and } seems strange, in MATLAB { and } are used for cell arrays and cell array indexing, not for code structuring. Further, the second argument for input must be 's', not 'y' as you have.

Fixed code:

choice = input('Do you want to print to file this 2D image ? [y/n] ', 's');

if(choice=='Y' || choice=='y')
    print(hFig, '-dpng', strcat(filename, '.png'));
end

Edit: to keep asking until user responds with 'y', 'Y', 'n' or 'N':

choice = '';
while ~ismember(choice, {'y', 'Y', 'n', 'N'})
    choice = input('Do you want to print to file this 2D image ? [y/n] ', 's');
end

if(choice=='Y' || choice=='y')
    print(hFig, '-dpng', strcat(filename, '.png'));
end

回答2:

So confusing! Because print command dont have any output argument!!!

I dont know clearly, but I think first of all check the hFig assignment. you can use

hFig=figure;
plot(X, Y, 'red');
% ...

if you want to create a figure and draw anything you want in it. as the error says your output argument is not assigned so check the "filename" or you can use

[filename '.png']

instead.

I hope this help you. right now I dont have MATLAB and I cant test it for you.

P.S. : See this : Why do I get the error '??? Output argument ‹variable› (and maybe others) not assigned during call to ‹function›.' ?

来源：https://stackoverflow.com/questions/10634678/error-with-print-output-argument-varargout-and-maybe-others-not-assigned

标签

matlab

printing