Matlab importdata text file

Question

I tried to import data from a text file. The data file format should be the first row are char and others are numbers, just like a xls file. But the file is generated by other software as a text file, where all data is in one row, with one space bar separated and 'tab' as a new row of data.

The data format I want to import into matlab should be like this:

But now the data in the text file is

A B C D   1 2 3 4   5 6 8 8   8 0 9 5

How should I import the text file into the matlab in a matrix like please? I tried importdata but the ans is 4x1 cell. My Matlab version is 2008.

Sorry I am very new to matlab. Thank you.

Edited: I realized that the data is

A B C D  1 2 3 4  5 6 8 8 8  8 0 9 5  7 0 8 8 8  5 0 9 9

Would you please teach me how to put these things into the cell, with one char/number one cell please?

Coz when i use cell2mat as suggested, error msg is CAT arguments dimensions are not consistent.

Thank you very much!

Because you have two different types (double and char), it's not possible to put everything in one matrix. That's the reason why ìmportdata produces a cell array. — bushmills

erfan erfan · Accepted Answer · 2016-09-21T07:48:58

Let's start with the cell array you generated from the text file. I call it A. It is a 4x1. Or maybe 1x4? With the following line we make sure that we are starting from the same point:

A = A(:); % make sure A is columnar

A is a cell array with the first element containing the names and from 2nd to the end containing numbers as string.

Case 1: Consistent size of each section: Making a matrix

Here we will see how to extract your desired matrix from this cell array.

First, we need strread to make a vector from a string (You can also use textscan):

v = strread(A{2})

v =

     1     2     3     4

Now we should apply this function on each cell and combine the vectors in a matrix. That could be achieved using cellfun, but since we have to first produce a cell array, at the end we will need a cell2mat:

M = cell2mat(cellfun(@strread, A(2:end), 'UniformOutput', false))

Here, M is the final result.

M =

     1     2     3     4
     5     6     8     8
     8     0     9     5

Case 2: Inconsistency in the sizes + combining char / number: Making a cell array

We want to transform the data into a cell array with each element occupying one cell. Starting from first row of celldata we can break the string of names into a cell array using strsplit:

celldata = strsplit(A{1});

% maximum data count in each cell of A
maxL = max(cellfun(@(x) numel(strsplit(x)), A));

% constructing an empty cell array to be filled with the data
% the importance of this step dramatically increases with the data size! 
celldata{numel(A), maxL} = [];

Now you can go through celldata and fill the cells of it with the proper values:

for ii = 2:numel(A)
    val = strread(A{ii});
    celldata(ii, 1:numel(val)) = num2cell(val);
end

celldata is a cell array in this form:

celldata = 

    'A'    'B'    'C'    'D'     []
    [1]    [2]    [3]    [4]     []
    [5]    [6]    [8]    [8]    [8]
    [8]    [0]    [9]    [5]     []
    [7]    [0]    [8]    [8]    [8]
    [5]    [0]    [9]    [9]     []

Matlab importdata text file

1 Answers