How do I write a loop in MATLAB that continues until the user presses any key?

Question

MathWorks Support Team 2010-2-5

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/100980-how-do-i-write-a-loop-in-matlab-that-continues-until-the-user-presses-any-key

回答： Xingwang Yong 2021-8-19

I want to run a specific routine in a loop. However I want the user to be able to exit the loop and end the routine by pressing any key on the keyboard.

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Answer 1

MathWorks Support Team 2010-2-5

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/100980-how-do-i-write-a-loop-in-matlab-that-continues-until-the-user-presses-any-key#answer_110328

在 MATLAB Online 中打开

MATLAB does not have a function that scans for keyboard activity without interrupting the event stream.

However, if your program involves a figure window, you can utilize the ‘KeyPressFcn’ property. The 'KeyPressFcn' is called when a key is pressed with an active figure window. You can set this function to change the state of a flag that ends a loop. Copy the following functions to a MATLAB file, and execute the MATLAB file.

function myLoopingFcn() 
global KEY_IS_PRESSED
KEY_IS_PRESSED = 0;
gcf
set(gcf, 'KeyPressFcn', @myKeyPressFcn)
while ~KEY_IS_PRESSED
      drawnow
      disp('looping...')
end
disp('loop ended')
function myKeyPressFcn(hObject, event)
global KEY_IS_PRESSED
KEY_IS_PRESSED  = 1;
disp('key is pressed')

The code will display "looping" in the MATLAB Command Window until a key is pressed when the figure window is active.

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Answer 2

Xingwang Yong 2021-8-19

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/100980-how-do-i-write-a-loop-in-matlab-that-continues-until-the-user-presses-any-key#answer_770474

在 MATLAB Online 中打开

A version uses nested function instead of global variable

function myLoopingFcn2() 
KEY_IS_PRESSED = 0;
gcf
set(gcf, 'KeyPressFcn', @myKeyPressFcn)
while ~KEY_IS_PRESSED
      drawnow
      disp('looping...')
end
disp('loop ended')
function myKeyPressFcn(hObject, event)
KEY_IS_PRESSED  = 1;
disp('key is pressed')
end
end