From: Eric Durant <edurant@umich.edu>
Subject: Re: Help Excel to Matlab, strings and numeric values
Date: 14 Jul 2000 00:00:00 GMT
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Matlab 5.3.1 has a similar problem when fetching data from Access 2000. 
Using the numeric mode option of DDEREQ ([1 0]), the last tuple is
always dropped.  When fetching in numeric mode, strings are converted to
the number 0.  When talking to Access, the string format data returned
is tab-delimited, so you can parse it through DLMREAD to get a numeric
matrix.  Here's the code I use to parse data from Access.  If Excel
returns tab-delimited data, this should work if you make the appropriate
modifications to the DDEREQ call:

===========================
dataString = ddereq(datachannel,'Data',[1 1]);
if isempty(dataString)
    error('Error while in DDEREQ')
elseif ~ischar(dataString)
    % Matlab 5.3.1 on WinNT4 returns the 1x1 double 0 on
    % large (>~500 kB) result sets
    error('Undocumented (non-char) return type from DDEREQ')
end
fn = tempname;
fid = fopen(fn, 'w');
if fid==-1
    error('Could not open temporary file')
end
count = fwrite(fid, dataString);
st = fclose(fid);
matrix = dlmread(fn, '\t');
delete(fn)
===========================

-- Eric Durant
   http://edurant.com/

David Nyarko wrote:
>I have data in Excel in which some of the columns are strings
>and some numerical values. I want to be able to read selected
>rows and columns into a MATLAB matrix and perform
>manipulations on the numeric values. My function is shown below
>as well as an example call to extract information from
>r1c1:r5c4 in the open EXCEL document (welltest1.xls)
>The problem I have is that the resulting MATLAB array displays
>correctly on the screen as shown, but the 'ischar' function
>indicates it is a character array, thus making it difficult to
>extract the numeric values in the actual EXCEL cells.
[...]