Changing the value in the popupmenu

Question

Quan Seah 2018-4-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/396712-changing-the-value-in-the-popupmenu

评论： Quan Seah 2018-4-23

The first item of my popupmenu is an instruction so it really isn't a value, but MATLAB seems to take it as a value whenever i accidentally pick it. Let's say I want to assign "5" to my second item, how do I make it show 5 instead of 2 because whenever I do the calculation MATLAB uses 2 instead of 5.

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Answer 1

Walter Roberson 2018-4-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/396712-changing-the-value-in-the-popupmenu#answer_316635

在 MATLAB Online 中打开

lookup_table = [nan, 5, 10, -4, 18];
idx = get(hObject, 'value');
if isempty(idx)
   ... user has not chosen anything
elseif idx > length(lookup_table)
   ... mismatch between lookup table and number of entries in String property
else
  associated_value = lookup_table(idx);
  if isnan(associated_value)
     ... opps, user chose a header.
  end
end

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Walter Roberson 2018-4-23

在 MATLAB Online 中打开

popChoice = contents{get(hObject,'Value')};
[tf, idx] = ismember(popChoice, {'Black', 'Brown', 'Red', 'Orange', 'Yellow', 'Green', 'Blue', 'Violet', 'Grey', 'White'});
if ~tf
  ... user choose a header or has not made any choice
else
  popVal = 10 * (idx-1);
end

Quan Seah 2018-4-23

在 MATLAB Online 中打开

The code doesn't seem to work either it is still showing the same value

 function firstmenu_Callback(hObject, eventdata, handles)
contents = cellstr(get(hObject,'String'));
popChoice = contents{get(hObject,'Value')};
[tf,idx] = ismember(popChoice, {'Black', 'Brown', 'Red', 'Orange', 'Yellow', 'Green', 'Blue', 'Violet', 'Grey', 'White'});
if ~tf
    ... user choose a header or has not made any choice
else
popVal = 10*(idx-1);
end

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