vertical concatenate strings in msgbox

Question

Jason 2023-1-28

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https://ww2.mathworks.cn/matlabcentral/answers/1902440-vertical-concatenate-strings-in-msgbox

编辑： Jason 2023-1-28

Hello,I cant understand why this vertical concatenation of strings isn't working.

    v = VideoReader(filename);              % Create Videoreader object
                    %Get info from video
                    D=['Duration(s): ',num2str(v.Duration,'%.2f')]
                    B=['BitsperPixel: ',num2str(v.BitsPerPixel)]
                    F=['FrameRate: ',num2str(v.FrameRate)]
                    N=['Num Frames: ',num2str(v.NumFrames)]
                    mstr=([D;F;B;N])
                    f = msgbox(mstr,'icon','help');
                    waitforbuttonpress;                %Block matlab until msgbox button is pressed

Gives an error: Dimensions of arrays being concatenated are not consistent

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Answer 1

cdawg 2023-1-28

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https://ww2.mathworks.cn/matlabcentral/answers/1902440-vertical-concatenate-strings-in-msgbox#answer_1158565

编辑：cdawg 2023-1-28

在 MATLAB Online 中打开

Each one of those isn't a string. If you look at D, F, B, and N in your workspace they are character vectors. For example, if I choose a value for duration:

D = ['Duraction(s): ', num2str(100)];
ischar(D)
ans = logical
   1
length(D)
ans = 17

D is as long as however may characters it has. That would mean that each of the vectors your concatenating would need to have the same number of characters.

But if I use "string" instead of 'character'

      D=["Duration(s): ",num2str(100)];
      isstring(D)
ans = logical
   1
      length(D)
ans = 2
      

Each vector will have a length of 2. If you want Duration and num2str to be together in one cell, try using strcat()

        D=strcat("Duration(s): ",num2str(100));    
        B=strcat("BitsperPixel: ",num2str(1000));
            F=strcat("FrameRate: ",num2str(10000));
            N=strcat("Num Frames: ",num2str(1000));
            mstr=([D;F;B;N])
mstr = 4×1 string array
    "Duration(s): 100"
    "FrameRate: 10000"
    "BitsperPixel: 1000"
    "Num Frames: 1000"

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Sulaymon Eshkabilov 2023-1-28

编辑：Sulaymon Eshkabilov 2023-1-28

在 MATLAB Online 中打开

Here strcat is not necessary. The straight and complete answer is the use of {} instead of [ ] to have the messaeg in the msgbox.

% v = VideoReader(filename); % Create Videoreader object

%Get info from video

v.Duration=4.70;

v.BitsPerPixel = 24;

v.FrameRate=30;

v.NumFrames=141;

D=['Duration(s): ',num2str(v.Duration,'%.2f')]

D = 'Duration(s): 4.70'

B=['BitsperPixel: ',num2str(v.BitsPerPixel)]

B = 'BitsperPixel: 24'

F=['FrameRate: ',num2str(v.FrameRate)]

F = 'FrameRate: 30'

N=['Num Frames: ',num2str(v.NumFrames)]

N = 'Num Frames: 141'

mstr=({D;F;B;N}) % Use braces

mstr = 4×1 cell array

{'Duration(s): 4.70'} {'FrameRate: 30' } {'BitsperPixel: 24' } {'Num Frames: 141' }

f = msgbox(mstr,'icon','help');

Jason 2023-1-28

编辑：Jason 2023-1-28

Oh i see, thankyou. Sorry i didnt accept your answer

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Answer 2

Sulaymon Eshkabilov 2023-1-28

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1902440-vertical-concatenate-strings-in-msgbox#answer_1158560

在 MATLAB Online 中打开

Here is the corrected code:

            v = VideoReader(filename);              % Create Videoreader object
            %Get info from video
            D=['Duration(s): ',num2str(v.Duration,'%.2f')]
            B=['BitsperPixel: ',num2str(v.BitsPerPixel)]
            F=['FrameRate: ',num2str(v.FrameRate)]
            N=['Num Frames: ',num2str(v.NumFrames)]
            mstr=({D;F;B;N})                        % Use braces       
            f = msgbox(mstr,'icon','help');
            waitforbuttonpress;                %Block matlab until msgbox button is pressed
            