logical data some time is not 0/1

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Luca Re 2023-7-19

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1997948-logical-data-some-time-is-not-0-1

评论： Luca Re 2023-7-19

1.png
2.png

        function startupFcn(app, setting)       
             app.Calling_Predy2=settings;
             app.UITable.ColumnName=["Strategy";"On";"Underlying";"Trading";"OOS";"Sipp.source";"Slippage";"Type";"Horizon";"Filter skip";"Static Size";"Min Size";"Max Size";"Min AvgTrade";"Select"];
             app.UITable.ColumnEditable=[false,true,false,true,true,true,true,true,true,true,true,true,true,true,true];
             cat = categories(app.Trading);cat2=categories(app.SlippSource);cat3=categories(app.Type);cat4=categories(app.Horizon);cat5=categories(app.SiNo);             
             colu={'char' 'logical' 'char' {cat{:}} 'char' {cat2{:}}  'char' {cat3{:}}  {cat4{:}}  {cat5{:}} 'char' 'char' 'char' 'char' 'logical'};                  
             app.UITable.ColumnFormat=colu; 
             app.SaveAsButton.Visible="off";
             app.SaveButton.Visible="off";
             app.Edit_Button.Visible='off';
             ...
             ..
             
            colu={'char' 'logical'.. ===> i set "logical" the second column of table
                
            
            then i go in app designer and i change value of "On" (pics 1.png), i save it
            and i check it using import(file)
            and i see similar to this (see 2.png)
            i see true and false.... (but having set the field as logical they should all be 0/1)
            
            
            
            
                

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Answer 1

Adam Danz 2023-7-19

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https://ww2.mathworks.cn/matlabcentral/answers/1997948-logical-data-some-time-is-not-0-1#answer_1275573

编辑：Adam Danz 2023-7-19

在 MATLAB Online 中打开

2.png indicates that the data is a 82x15 string where some values in col 2 are in the form "true"/"false" whereas other values in col 2 are in the form "0". How are you reading in this data? You can convert this mix of strings to a logical vector using one of the options below.

Option 1: string comparison

str = ["false","1","true","0"];
bool = ismember(lower(str),["true","1"])
bool = 1×4 logical array
   0   1   1   0

However, if any unexpected values such as "2" appear in the string, this will convert them to false. To validate the conversion, this line will throw an error if there are any unexpected strings.

assert(all(ismember(lower(str),["true","false","1","0"])),"String values must represent boolean values.")

Option 2: Class conversion

str = ["false","1","true","0"];
bool = arrayfun(@(s)logical(str2num(s)),str)
bool = 1×4 logical array
   0   1   1   0

However, if any unexpected values such as "2" or "F" appear in the string, this may either throw an error or silently return a logical value. To validate the conversion, use the same assert validation in option 1.

Option 3: Specify varopts when reading the data

If these data are read into MATLAB, you could use T = readtable(filename,opts) and set opts using setvaropts. In setvaropts you can specify,

opts = setvaropts(opts,'mybool',...
    "TrueSymbols",["true","1"],...
    "FalseSymbols",["false","0"]);

This is demonstrated well in this answer by @Jeremy Hughes.

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Luca Re 2023-7-19

移动：Voss 2023-7-19

在 MATLAB Online 中打开

4.png
3.png

hi,thank for answer

You write: "How are you reading in this data? "

Simple..see pics 3-4

in the starting situation they are all "1" ..therefore the values are correct The problems come when I click on the box

I click on the box to select or deselect it.. then it's the code that does the update

i use this function to update the data you enter in the table.. but I've seen that it doesn't always update them

     function UITableCellSelection(app, event)
            %indices = event.Indices;
             app.MyTable=app.UITable.Data; %MESSO PER VIA DI UN BUG DI MATLAB CHE NON AGGIORNA LA TABELLA! 
             disp(app.MyTable(:,2))
             [r,~]=size(app.MyTable); %%MI AGGIORNA IL NUM STRATEGIE
             app.CurrentNumberStrategy=double(r);
             app.TotalstrategiesloadedTextArea.Value=string(r);
             app.SaveAsButton.Visible="off";
             app.SaveButton.Visible="off";   
     end
     

Adam Danz 2023-7-19

在 MATLAB Online 中打开

Thanks for the explanation. This is because the logical values are converted to strings:

string(true)
ans = "true"
string(false)
ans = "false"

Instead of storing the data in a string array, is there a reason you could not use a table in which case the column that stores these values can be logical?

Luca Re 2023-7-19

11.png

i want to use a table because i am displaying data in table format in app designer

I can however convert the data before it is saved to app.MyTable=app.UITable.Data;

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