Reading text file to extract specific data chunks

I have a large text file with important numbers about a certain category. It looks something like this

CATEGORY 1
*        1
*        2
*        3
*        4

CATEGORY 2
*        4
*        5
*        6
*        7

CATEGORY 3
*        8
*        9
*       10
*       11

There are many more categories, but for the example I'll keep it at these two. Depending on a user input, I want to fill a variable, lets call it "numbers" with the numbers under the appropriate category. Say a user inputs "CATEGORY 2", I want the variable "numbers" to be [4 5 6 7]. How could I do this? I'm trying to use fgetl and simply index the number on each line, but I can't get it right. Any help is appreciated!

Edit: Included actual text file being read. Also included the code I've tried with the error I'm getting

component = input('Write the component being analyzed in quotes:   ')

fid = fopen(‘stations_clgrids.txt')

station = [];

i = 1;


if component == 'Fairing'
    while ~feof(fid)
        line = fgetl(fid);
        if (line(1:7) == 'FAIRING')
            line_sta = fgetl(fid);
            if (line_sta(1)=='*')
                station(i) = str2num(line_sta(9:16))
            elseif isempty(line_sta)
                break
            end
        end
    end
end


Write the component being analyzed in quotes:   'Fairing'
Index exceeds the number of array elements (0).

Error in define_cl_station (line 13)
        if (line(1:7) == 'FAIRING') 

[Star Strider]

I have no idea what you want to do with the contents of that file, so I deleted my answer.

Answer 1

[Image Analyst]

Try it this way:

% component = input('Write the component being analyzed in quotes:   ')
component = 'Fairing'
fid = fopen('stations_clgrids.txt', 'rt')
station = [];
index = 1;
if strcmpi(component, 'Fairing')
    while ~feof(fid)
        textLine = fgetl(fid);
        fprintf('Just read "%s" from file.\n', textLine)
        if contains(textLine, 'FAIRING', 'IgnoreCase',true)
            starredLine = fgetl(fid);
            fprintf('    Just read starred line "%s" from file.\n', starredLine)
            if startsWith(starredLine, '*')
                station(index) = str2num(starredLine(2:end));
                % Increment counter.
                index = index + 1;
            elseif isempty(starredLine)
                break
            end
        end
    end
end
fclose(fid);
% Show in command window
station

[Zain Jamal]

Used a variation of this

if strcmpi('Fairing',component) %if the user wants the fairing analyzed
    while ~feof(fid) %read until end of file is reached
        if size(line,2)>1 %don't read empty lines
            if strcmpi('FAIRING CENTERLINE GRIDS',line) %start reading the cl grids
                i_1 = i; %set the beginning index
                line = fgetl(fid); %read the next line
                i = i + 1; %increase the index
                chkstr = [line '                                   ']; %expand the line size to be readable
                while ~strcmpi(chkstr(1:3), 'END') %read until the word END is reached next
                    line = fgetl(fid); %read the line
                    i = i + 1; %increase the counter
                    clgrid(i) = str2num(chkstr(9:16)); %fill in the clgrid values
                    chkstr=[line '                                   ']; %expand the line again just in case
                end
                i_2 = i; %set final index where data is no longer read
                clgrid = clgrid(i_1+2:i_2); %omit zeros 
                break;break;break;
            else
                line = fgetl(fid); %read rest of file
                i = i + 1;
            end
        else
            line = fgetl(fid); %read rest of file
            i = i + 1;
        end 
    end

[Image Analyst]

Yeah, that's not so good for many reasons, but whatever.