MATLAB: Request user input and using that ans for the functions

matlab gui

How can I use the user's input and convert it to a numerical value to be used in my remaining codes?

prompt=('Enter a threshold value to convert the grayscale image to black and white: ');
dlg_title=('Threshold level value');
num_lines=1;
defaultans={'0.5'};
answer=inputdlg(prompt,dlg_title,num_lines,defaultans);

Best Answer

>> val = str2double(answer{1})
val =
     3

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MATLAB: How to read user input of multiple string separately in inputdlg

Here's a snippet I post regularly:

% Ask user for two floating point numbers.
defaultValue = {'45.67', '78.91'};
titleBar = 'Enter a value';
userPrompt = {'Enter floating point number 1 : ', 'Enter floating point number 2: '};
caUserInput = inputdlg(userPrompt, titleBar, 1, defaultValue);
if isempty(caUserInput),return,end; % Bail out if they clicked Cancel.
% Convert to floating point from string.
usersValue1 = str2double(caUserInput{1})
usersValue2 = str2double(caUserInput{2})
% Check usersValue1 for validity.
if isnan(usersValue1)
    % They didn't enter a number.  

    % They clicked Cancel, or entered a character, symbols, or something else not allowed.

  % Convert the default from a string and stick that into usersValue1.
    usersValue1 = str2double(defaultValue{1});
    message = sprintf('I said it had to be a number.\nTry replacing the user.\nI will use %.2f and continue.', usersValue1);
    uiwait(warndlg(message));
end
% Do the same for usersValue2
% Check usersValue2 for validity.
if isnan(usersValue2)
    % They didn't enter a number.  
    % They clicked Cancel, or entered a character, symbols, or something else not allowed.
  % Convert the default from a string and stick that into usersValue2.
    usersValue2 = str2double(defaultValue{2});
    message = sprintf('I said it had to be a number.\nTry replacing the user.\nI will use %.2f and continue.', usersValue2);
    uiwait(warndlg(message));
end

MATLAB: Troubleshooting code for prompt and inputdlg

You need to convert ‘answer’ to a number:

N=str2double(answer);

That should work with your code.

Best Answer

Related Solutions

MATLAB: How to read user input of multiple string separately in inputdlg

MATLAB: Troubleshooting code for prompt and inputdlg

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