How can i change this to a multiselect loop?

I have this code file that works but i would like to change it to multiselect and run a loop to process the data.

function [M1,YT] = read6840(fid)
[FileName, PathName]=uigetfile({'*.asc','Individual DAS Files (*.asc)'},...
    'Select 6840 Word File');
fid=fopen([PathName FileName]);
info6840=textscan(fid,'%10s',43);
data6840=textscan(fid,'%15s %5s %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %s %s %s',15000);
fclose(fid);
% Record Information
DATE =char(info6840{:}(1));
DATE=[DATE(4:5) '/' DATE(7:8) '/' DATE(1:2)]; %convert to MM/DD/YY
RECORD =char(info6840{:}(40));
CH =char(info6840{:}(41));
S=char(info6840{:}(42));
%LOCKON =char(info6840{:}(43));
% Assign Variables to Names
for n=5:38
    eval([char(info6840{:}(n)) '=data6840{' num2str(n-2) '};'])
end
time6840=(0:1:length(XDOT)-1)'*.05;
% Assign Discrete Variables to Names
ZW=char(ZW);
STAT=char(STAT);
BUS=char(BUS);

This is how i attempted to change it. Based on another bit of code I have that successfully runs multiselect loop

function [M1,YT] = read6840(varargin)
if nargin==0
    [FileName,PathName] = uigetfile('*.asc','Select 6840 Word File ','MultiSelect','on');
    if isnumeric(FileName)
        %User clicked cancel or closed the window
        return
    end
else
    FileName = varargin{1};
    if nargin > 1
        PathName = varargin{2};
    else
        PathName = cd;
    end
    if nargin > 2
        OutPath = varargin{3};
        if exist(OutPath,'dir') ~= 7
            mkdir(OutPath);
        end
    else
        OutPath = PathName;
    end
end
FileName = compose('%g',FileName);
NumOfFiles = length(FileName);
GoodFiles = 1:NumOfFiles;
SN = zeros(NumOfFiles,1);
T = zeros(NumOfFiles,1);
H = zeros(NumOfFiles,1);
C = zeros(NumOfFiles,1);
CH = cellstr(repmat('C',NumOfFiles,1));
MC = cellstr(repmat('UNK',NumOfFiles,1));
WS = cellstr(repmat('UNK',NumOfFiles,1));
WD = cellstr(repmat('UNK',NumOfFiles,1));

for inx=1:NumOfFiles  %Multifile loop begin
    fid=fopen(FileName);
    info6840=textscan(fid,'%10s',43);
    %     if ~strcmp('6840',info6840{:}(3))
    %         %Not a 6840 file... skip and move on.
    %         fclose(fid);
    %         GoodFiles(inx) = -1; %Remove this entry from the good files list.
    %         continue
    %     else %Valid 6840 file
    %         data6840=textscan(fid,'%15s %5s %20s %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %s %s %s %s %s');
    %         fclose(fid);
    %         
    %         % check data6840 for good data
    %         for ii=1:size(data6840,2)
    %             if isempty(data6840{1,ii})
    %                 %Not a good file... skip and move on.
    %                 GoodFiles(inx) = -1; %Remove this entry from the good files list.
    %                 continue
    %             end
    %         end
    %         clear ii
    %         
    %     %If we get this far, this is a good file.
    %     end
    %             data6840=textscan(fid,'%15s %5s %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %s %s %s',15000);
    %             fclose(fid);
    
    % Record Information
    DATE =char(info6840{:}(1));
    DATE=[DATE(4:5) '/' DATE(7:8) '/' DATE(1:2)]; %convert to MM/DD/YY
    RECORD =char(info6840{:}(40));
    CH =char(info6840{:}(41));
    SN=char(info6840{:}(42));
    %LOCKON =char(info6840{:}(43));
    
    % Assign Variables to Names
    for n=5:38
        eval([char(info6840{:}(n)) '=data6840{' num2str(n-2) '};'])
    end
    
    time6840=(0:1:length(XDOT)-1)'*.05;
    
    % Assign Discrete Variables to Names
    ZW=char(Z11LW);
    STAT=char(STAT);
    BUS=char(BUS);
end

Answer 1

[Voss]

It's not clear exactly what read6840 is intended to do, so I can only offer an outline of how it might look operating on multiple files:

function read6840(varargin)

% I don't know what the output(s) of this function are (M1 and YT are not
% defined in your code), but whatever they are, they can be initialized
% here to avoid 'Undefined' error in case the user clicks cancel and the
% function returns early.

if nargin == 0
    % no inputs given; prompt the user to select some files:
    [FileName,PathName] = uigetfile('*.asc','Select 6840 Word File ','MultiSelect','on');
    if isnumeric(FileName)
        % User clicked cancel or closed the window
        return
    end
else
    % FileName given as input:
    FileName = varargin{1};
    if nargin > 1
        % PathName also given as input:
        PathName = varargin{2};
    else
        % PathName not given as input; use the current working directory:
        PathName = pwd();
    end
    if nargin > 2
        % OutPath given as input:
        OutPath = varargin{3};
        % if it doesn't exist, create it:
        if ~isfolder(OutPath)
            mkdir(OutPath);
        end
    else
        % OutPath not given as input; use PathName:
        OutPath = PathName;
    end
end

% if one file was selected, then FileName is a character vector (a
% character vector might have been passed in as the first argument as
% well), so make it a cell array:
if ischar(FileName)
    FileName = {FileName};
end

% get full-path file names:
FileName = fullfile(PathName,FileName);

% initialize these variables:
NumOfFiles = numel(FileName);

SN = zeros(NumOfFiles,1);
T = zeros(NumOfFiles,1);
H = zeros(NumOfFiles,1);
C = zeros(NumOfFiles,1);

CH = cell(NumOfFiles,1);
MC = cell(NumOfFiles,1);
WS = cell(NumOfFiles,1);
WD = cell(NumOfFiles,1);

% loop over files:
for inx = 1:NumOfFiles
    
    % open the current file:
    fid = fopen(FileName{inx});
    
    % ... code to read the file ...
    
    % close the current file:
    fclose(fid);
    
    % ... code to do whatever you're going to do with this file's contents ...
    
    % ... e.g., populate one element of SN, T, etc.:
    
    SN(inx) = % ...
    T(inx) =  % ...
    H(inx) =  % ...
    C(inx) =  % ...
    
    CH{inx} = % ...
    MC{inx} = % ...
    WS{inx} = % ...
    WD{inx} = % ...
    
    % ... whatever else ...
    
end

% ... whatever else ...

end