How can I handle multiple files at their import ?

Hello everyone,

I have implemented a matlab code, which import data from a text file in order to calculate some statistics. When the code is executed, the user defines the "filemode" and a system "gnss", which are both combined to a string that leads to a txt file named filemodegnss.pos.

clear all;
close all;
format long;

msg1 = 'Specify your filemode [e.g. unb3_M1S_A] => ';
filemode = input(msg1, 's');

msg2 = 'Specify your GNSS [e.g. g/gr/ge/grec] => ';
gnss = input(msg2, 's');

filename = [filemode gnss '.pos'];
f = fopen(filename, 'r');

if gnss == 'g'
    startRow = 19;
else startRow = 20;
end

formatSpec = '%10s%13s%15s%15s%15s%4s%4s%9s%9s%9s%9s%9s%9s%7s%s%[^\n\r]';
dataArray = textscan(f, formatSpec, 'Delimiter', '', 'WhiteSpace', '', 'HeaderLines' ,startRow-1, 'ReturnOnError', false);
fclose(f);

raw = repmat({''},length(dataArray{1}),length(dataArray)-1);
for col=1:length(dataArray)-1
    raw(1:length(dataArray{col}),col) = dataArray{col};
end
numericData = NaN(size(dataArray{1},1),size(dataArray,2));

for col=[3,4,5,6,7,8,9,10,11,12,13,14,15]
    % Converts strings in the input cell array to numbers. Replaced non-numeric
    % strings with NaN.
    rawData = dataArray{col};
    for row=1:size(rawData, 1);
        % Create a regular expression to detect and remove non-numeric prefixes and
        % suffixes.
        regexstr = '(?<prefix>.*?)(?<numbers>([-]*(\d+[\,]*)+[\.]{0,1}\d*[eEdD]{0,1}[-+]*\d*[i]{0,1})|([-]*(\d+[\,]*)*[\.]{1,1}\d+[eEdD]{0,1}[-+]*\d*[i]{0,1}))(?<suffix>.*)';
        try
            result = regexp(rawData{row}, regexstr, 'names');
            numbers = result.numbers;

              % Detected commas in non-thousand locations.
              invalidThousandsSeparator = false;
              if any(numbers==',');
                  thousandsRegExp = '^\d+?(\,\d{3})*\.{0,1}\d*$';
                  if isempty(regexp(thousandsRegExp, ',', 'once'));
                      numbers = NaN;
                      invalidThousandsSeparator = true;
                  end
              end
              % Convert numeric strings to numbers.
              if ~invalidThousandsSeparator;
                  numbers = textscan(strrep(numbers, ',', ''), '%f');
                  numericData(row, col) = numbers{1};
                  raw{row, col} = numbers{1};
              end
          catch me
          end
      end
  end

dateFormats = {'Enter custom format here.', 'HH:MM:SS'};
for col=[1,2]% Convert the contents of column with dates to serial date numbers using date format string (datenum).
    for row=1:length(dataArray{col})
        try
            numericData(row, col) = datenum(dataArray{col}{row}, dateFormats{col==[1,2]});
            raw{row, col} = numericData(row, col);
        catch me
        end
    end
end

%%Replace non-numeric cells with NaN
R = cellfun(@(x) ~isnumeric(x) && ~islogical(x),raw); % Find non-numeric cells
raw(R) = {NaN}; % Replace non-numeric cells

%%Create output variable
P = cell2mat(raw);
%%Clear temporary variables
clearvars filename startRow formatSpec fileID dataArray ans raw col numericData rawData row regexstr result numbers invalidThousandsSeparator thousandsRegExp me dateFormats R;

for n = 1:(size(P,1))
    X       = P(n,3);
    sigmaX  = P(n,8);
    Y       = P(n,4);
    sigmaY  = P(n,9);
    Z       = P(n,5);
    sigmaZ  = P(n,10);
    Coords(n,:) = [X sigmaX Y sigmaY Z sigmaZ];
end

obsperiod = input('Specify the obs period [Press 24, 12, 6, 4, 2, 1, 0.5 h] => ');

if obsperiod == 24
    t = 24;
    C = Coords(t*60*2,:)

elseif obsperiod == 12
    t = 12;
    C1 = Coords(1*(t*60*2+1)-0,:);
    C2 = Coords(2*(t*60*2+1)-1,:);
    C = [C1; C2]

elseif obsperiod == 6
    t = 6;
    for i = 1:(24/t)
        C1(i,:) = Coords(i*(t*60*2+1-1),:);
    end
    C = C1

elseif obsperiod == 4
    t = 4;
    for i = 1:(24/t-1)
        C1(i,:) = Coords(i*(t*60*2+1),:);
    end
    C2 = Coords((24/t)*(t*60*2+1)-1,:);
    C = [C1; C2]

elseif obsperiod == 2
    t = 2;
    for i = 1:(24/t)
        C1(i,:) = Coords(i*(t*60*2+1-1),:);
    end
    C = C1

elseif obsperiod == 1
    t = 1;
    for i = 1:(24/t)
        C1(i,:) = Coords(i*(t*60*2+1-1),:);
    end
    C = C1

elseif obsperiod == 0.5
    t = 0.5;
    for i = 1:(24/t)
        C1(i,:) = Coords(i*(t*60*2+1-1),:);
    end
    C = C1

elseif obsperiod == 0.25
    t = 0.25;
    for i = 1:(24/t-1)
        C1(i,:) = Coords(i*(t*60*2+1),:);
    end
    C2 = Coords((24/t)*(t*60*2+1)-1,:);
    C = [C1; C2]
end

avgsdx = mean(C(:,2));
avgsdy = mean(C(:,4));
avgsdz = mean(C(:,6));

RMSx = rms(C(:,2));
RMSy = rms(C(:,4));
RMSz = rms(C(:,6));

What I want to do is define more systems called "GNSS" in the start of the program's execution and give a different name to the P matrix that it's made later in order to handle their data. How exactly can I do this ? I tried to do a while loop like this below, in order to define my systems and map the filemode with every each system GNSS, but when I call "exit" to terminate the loop and move on, the code still wants my to insert an input:

msg2 = 'Specify your GNSS =>';
while strcmp(msg2, 'exit')
  gnss = input(msg2, 's');
  msg2 = 'Specify your GNSS =>'
end

Any suggestion ?

Thank you in advance.

Answer 1

[Geoff Hayes]

Dimitris - if msg2 is set to 'exit' then

 strcmp(msg2,'exit')

will always return 1 and so the code will never exit the while loop. But then, msg2 is only ever assigned the string 'Specify your GNSS =>' which is never 'exit' and so the we'll never enter the while loop. A paradox? :)

You probably need to do something like

 gnss = input('Specify your GNSS => ', 's')
 while ~strcmpi(gnss, 'exit')

     % do stuff

     gnss = input('Specify your GNSS => ', 's')
 end

Note how we only enter the while loop if the gnss string is not 'exit'. We use the strcmpi to ignore case so that 'Exit', 'exit', 'ExIt', etc. are all equivalent.

[Dimitris Psychas]

Yeah, you are right :) Thank you very much for your notes.

But do you know how exactly can I map my inputs ? For instance check the code below. First, I insert a mode, let's say unb3_M1S_A. Then, I want to have the cabability to insert a lot of GNSS systems at once, like G or GR and have the data files made automatically, like unb3_M1S_Ag.pos and unb3_M1S_Agrec.pos so as not to type them interactively due to the large number of files I want to handle.

msg1 = 'Specify your filemode [e.g. unb3_M1S_A] => ';
filemode = input(msg1, 's');

msg2 = 'Specify your GNSS [e.g. g/gr/ge/grec] => ';
gnss = input(msg2, 's');

filename = [filemode gnss '.pos'];
f = fopen(filename, 'r');