How to read specific part of the text file?

So, I have text file in Notepad data.txt which contain all information about some image for example

• image1.gif
• gif
• 256
• 256
• 155.992455 321.222455 995.452774 741.123478
• 15 24 35
• 41 52 64
• 58 59 50

so I have name of image, extension,height, width, matrix of gray image and matrix of image in this order in file. I made function which receives namefile and parameter which is needed to be read. So I want that the result of function be that parametar from text file for example function:

readformfile('data.txt','MatrixOfImage')

and result should be this

15 24 35

41 52 65

58 59 50

I have written the function but it reads all text from file and I don't know how to read only specific parameter from file

function result=readfromfile(namefile,parameter)
result=fileread(namefile);

end

I would be very grateful if someone could help me.

[dpb]

I'd probably just build a routine that reads the whole file then sends back the section(s) requested. That way it's all one function to maintain and simply a choice of which data to return. Of course, if you think you're going to be looking at the same file over and over for various pieces, that's a lot of overhead so I'd try to rearrange my higher level usage to avoid that. Memory is cheap these days...so what if you've got some extra stuff hanging around waiting to be used later?

[Lolipop]

Well I made some routine that reads file by section. I just put for example # at the end of every section and then with function strread do this

[a,b,c,d,e,f]=strread(text,'%s %s %s %s %s %s','delimiter','#');

And then I have all section but how to get one I need?

Answer 1

[per isakson]

With Matlab there are many ways. The one below is one of them. Regard the first five lines as a "header" and use textscan.

    >> num = cssm()
    num =
        15    24    35
        41    52    64
        58    59    50

where

    function    num = cssm() 
        fid = fopen( 'cssm.txt' );
        cac = textscan(fid,'%f%f%f', 'Headerlines',5, 'CollectOutput',true );
        fclose( fid );
        num = cac{1};
    end

and cssm.txt contains

    image1.gif
    gif
    256
    256
    155.992455 321.222455 995.452774 741.123478
    15 24 35
    41 52 64
    58 59 50

&nbsp

In response to comment

Try this modified function

    >> out = cssm( 'cssm1.txt', 'name_of_image' )
    out =
    image1.gif
    >> out = cssm( 'cssm2.txt', 'color_image' )
    out =
        78    44    28
        77    32    71
        55    12    53
    >> out = cssm( 'cssm2.txt', 'RBG_image' )
    name_of_image, extension, height, width, gray_image, color_image
    out =
         []
    >> out = cssm( 'cssm1.txt', 'width' )
    out =
       256

where

    function    out = cssm( filespec, param ) 

        fid = fopen( filespec );
        cac = textscan( fid, '%s', 'Delimiter','\n', 'CollectOutput',true );
        fclose( fid );

        switch lower( param )
            case 'name_of_image'
                out = cac{1,1};
            case 'extension'
                out = cac{2,1};
            case 'height'
                out = str2double( cac{3,1} );
            case 'width'
                out = str2double( cac{4,1} );
            case 'gray_image'
                out = str2num( cac{5,1} );
            case 'color_image'
                out = str2num( char(cac(6:8,1)) );
            otherwise
                str = 'name_of_image, extension, height, width, gray_image, color_image';
                disp( str )
                out = [];
        end
    end

and cssm2.txt contains

    image2.gif
    gif
    128
    128
    456.972255 333.2147455 895.441274 125.111278
    78 44 28
    77 32 71
    55 12 53

[Lolipop]

This works..but I want when user use this function he can choose text file and parameter from text file and then that parameter write in commamd window.

So the name of text file and parameters (name of image, extension,height, width, matrix of gray image and matrix of image) are known only when user type them in.

For example user wants from file cssm.txt width of image and this function should give him width. Or user wants from another text file data.txt only extension from file.

I hope that you understand me what I'm trying to do...

[per isakson]

What about "I made function which receives namefile and parameter which is needed to be read." ?

[Lolipop]

Sorry of my bad English..what I meant I made this

function result=readfromfile(namefile,parameter)
result=fileread(namefile);
end

I know what function receives,but I don't know how to write it?

[per isakson]

No, I don't get it. I need more detailed descriptions of

• parameter
• result

[Lolipop]

Ok..I tried to do this task alone,but it doesn't work so I tried to explain you what I have done but I only confused you because of my bad English,so for a moment let's forget what I have done with this task. This program should display specific part of some text file. There are 4 text files.In each of 4 text files there are 6 parameters written in this order

Data1.txt

    image1.gif
    gif
    256
    256
    155.992455 321.222455 995.452774 741.123478
    15 24 35
    41 52 64
    58 59 50

so I have name of image, extension,height, width, matrix of gray image and matrix of image in this order in file. Of course in second file there is the same order of parametres only with different numbers.

Data2.txt

    image2.gif
    gif
    128
    128
    456.972255 333.2147455 895.441274 125.111278
    78 44 28
    77 32 71
    55 12 53

And so on.

So when user starts this function he can choose which text file and parameter from that text file he wants to display.

For example user should call function something like this

>> readfromfile('Data1.txt','width')

and result should be

>> 256

Hope you understand

If you have some question please ask me :)

[Lolipop]

Oh my God this is really working...THANK YOU SO MUCH... and please could you explain me this line

out = str2num( char(cac(6:8,1)) );

how you get whole matrix to display

[per isakson]

Now I got it! I added a new function to the answer.

[per isakson]

"explain me this line"

    out = str2num( char(cac(6:8,1)) );

Run

    cac = { '15 24 35'
            '41 52 64'
            '58 59 50' }
    % convert the cell array of strings to a character array 
    str = char( cac )       
    % convert the character array to a double array
    num = str2num( str )

it displays

    cac = 
        '15 24 35'
        '41 52 64'
        '58 59 50'
    str =
    15 24 35
    41 52 64
    58 59 50
    num =
        15    24    35
        41    52    64
        58    59    50

and run

    >> whos
      Name      Size            Bytes  Class     Attributes
      cac       3x1               384  cell                
      num       3x3                72  double              
      str       3x8                48  char

[Lolipop]

I got it! You really helped me a lot...Thank you for your time and if there is some another way to thank you,tell me :)