MATLAB: Convert a text file to a matrix

convertmatrixstringstringstext file

Hello.

I have a text file with columns delimited by tabs. I have to convert it to a matrix. I have the following problems :

sometimes, there is two or more tabs in a row. It means that there is a blank cell.
sometime, two words are seperated by a point. When this happens, it doesn't mean that they are in different cells! Only the "tab" is a delimiter.
the collumns and lines are not always the same lenght.

Exemple of one line :

00982 FILE 2 Dupont Mary, May FEMALE 23.04.1999 0 89 11 23 2.01.2017 14:02:30 168 55 19.49 128 LABHUTC Yes 789 123 8 5 2 4 3

At first, I tried to use "strsplit(U)" but because of the problems I enonced, it doesn't work.

Oh and when I copy and paste the text file in excel, it gives me the right table.

Thank you very much in advance!

Best Answer

fun = @(s)regexp(s,'\t','split');
[fid,msg] = fopen('DML001_Carotid_Pressure_6.txt','rt');
assert(fid>=3,msg)
hdr = fun(fgetl(fid));
val = fun(fgetl(fid));
str = fgetl(fid);
while isempty(str)
	str = fgetl(fid);
end
col = numel(fun(str));
out = {};
while ~feof(fid)
	str = fgetl(fid);
	tmp = str2double(fun(str));
	tmp(end+1:col) = NaN;
	out{end+1} = tmp;
end
fclose(fid);
mat = vertcat(out{:})

Giving:

mat =
   567.000   187.000    61.050    70.000
   215.000   288.000    69.350    69.120
   217.000   289.000    71.520       NaN
   219.000   291.000       NaN       NaN

Bonus: convert the header to a structure:

hdr = regexprep(hdr,'\W','_')
val(end+1:numel(hdr)) = {''};
S = cell2struct(val(:),hdr(:),1);

Giving:

>> S.Surname
ans = Dupont
>> S.HEIGHT
ans = 168
>> S.System_ID
ans = 00982
etc.

Related Solutions

MATLAB: Read mulitple files in matlab

dinfo = dir('*.txt');
for K = 1 : length(dinfo)
  thisfilename = dinfo(K).name;  
 %read the file 
end

Read about load, importdata_, textscan to load whole text file data instead of reading line by line.

MATLAB: Using regexp for space delimited strings in text file.

Try this:

% textscan options:
opt = {'MultipleDelimsAsOne',true,'CollectOutput',true};
% required arrays:
str = 'X';
dtv = [];
dat = {};
% open textfile:
fid = fopen('data.txt','rt');
while ischar(str)
    % skip lines until first char is '*' (date vector):
    while ~strcmp(str(1),'*')
        str = fgetl(fid);
    end
    % convert date vector to numeric:
    dtv(end+1,:) =  str2double(regexp(str(2:end),'\S+','match')); %#ok<SAGROW>

    % get file position:
    pos = ftell(fid);
    % read first line of matrix:
    str = fgetl(fid);
    if ischar(str)
        % calculate how many columns in the matrix:
        N = numel(regexp(str(5:end),'\S+','match'));
        fmt = repmat('%f',1,N);
        % rewind one line:
        fseek(fid,pos,'bof');
        % read entire matrix:
        dat{end+1} = textscan(fid,['%4[^*]',fmt],opt{:}); %#ok<SAGROW>
    end
end
% concatenate data in cell arrays:
dat = vertcat(dat{:});
mat = vertcat(dat{:,2});

This reads the entire data matrix (between the date vectors) into a numeric matrix inside the cell array dat, and the date vectors in dtv. It automatically adjusts for the different numbers of columns in your matrices. Some important assumptions:

the first columns comprise of exactly four characters (which may be spaces).
the date vectors always start with asterisks, but no other lines do.
no empty lines between the date vectors and the data matrices.
the matrices contain numeric data only.

Have a look inside dat, and pick the data that you need:

>> cell2mat(cellfun(@(m)m(1,[1,2,3]),dat(:,2),'UniformOutput',false))
ans =
   1.0e+04 *
    0.6445   -2.4080   -0.8935
    0.6645   -2.2892   -1.1498

I also concatenated the matrices into mat, which lets gives you all of the matrices in one. This might be easier to access:

>> mat([1,10],[1,2,3])
ans =
   1.0e+04 *
    0.6445   -2.4080   -0.8935
    0.6645   -2.2892   -1.1498

I tested this code on both of the files that you have provided (this question, and your last question), which are also available here:

Best Answer

Related Solutions

MATLAB: Read mulitple files in matlab

MATLAB: Using regexp for space delimited strings in text file.

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