Textscan and Regexp Cell Data Layout

I'm trying to make some logic work with some legacy matlab code. I figured the easist thing was to make the data look the same as what the code is expecting.

I'm reading the relevant data from a CSV file, it's pretty simple -- but the format for the IDs changed from a simple number to an ID of the form [YY,ZZZZ].

As an example, the 'previous' CSV data looked like:

1,Simple,Data
2,More,Data
3,Even,More
4,Really,More

The 'new' CSV data looks like:

[01,0001],Simple,Data
[02,1001],More,Data
[03,9876],Even,More
[04,1234],Really,More

Previously, to read in the data, this logic was used:

 fid = fopen(fileName);
 data = textscan(fid,'%s%s%s%*s','Delimiter',',');

When this was done against the 'previous' CSV data, it returned data that look like this:

data =
  1×3 cell array
    {4×1 cell}    {4×1 cell}    {4×1 cell}    

The cells then look like:

K>> data{:}

ans =

  4×1 cell array

    '1'
    '2'
    '3'
    '4'


ans =

  4×1 cell array

    'Simple'
    'More'
    'Even'
    'Data'


ans =

  4×1 cell array

    'Data'
    'Data'
    'More'
    'Data'

So to handle the ID of the form [YY,ZZZZ], I had to modify the 'textscan' logic to handle the new ID format that we're using. To do that, I'm using a regexp function:

fid = fopen(fileName);
rawData = textscan(fid,'%s','Delimiter','\n');
data = regexp(rawData{1},'[ \-\/\w]*([\[][^\)\]]*[\]])?', 'match')

This then, after it reads in the data, gives me data that is formatted like this:

K>> data

data =

  4×1 cell array

    {1×3 cell}
    {1×3 cell}
    {1×3 cell}
    {1×3 cell}

K>> data{:}

ans =

  1×3 cell array

    '[01,0001]'    'Simple'    'Data'


ans =

  1×3 cell array

    '[02,1001]'    'More'    'Data'


ans =

  1×3 cell array

    '[03,9876]'    'Even'    'More'


ans =

  1×3 cell array

    '[04,1234]'    'Really'    'More'

So you can see that it has the correct data in it -- but the data is laid out differently which is breaking on the legacy code. So my question is how can I make the 'new' data be laid out like this as it was coming out of the 'textscan' logic:

data =
  1×3 cell array
    {4×1 cell}    {4×1 cell}    {4×1 cell}  

Answer 1

[Pujitha Narra]

Hi Mark,

This could be a possible workaround for your requirement:

data = textscan(fid,'%s%s%s%s%*s','Delimiter',',');
data{1}=strcat(data{1},{','},data{2}); % to retrieve the ID in its original format
>> data{:}

ans =

  4×1 cell array

    {'[01,0001]'}
    {'[02,1001]'}
    {'[03,9876]'}
    {'[04,1234]'}


ans =

  4×1 cell array

    {'0001]'}
    {'1001]'}
    {'9876]'}
    {'1234]'}


ans =

  4×1 cell array

    {'Simple'}
    {'More'  }
    {'Even'  }
    {'Really'}


ans =

  4×1 cell array

    {'Data'}
    {'Data'}
    {'More'}
    {'More'}

Hope this helps!