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From: Nicholas Kinar on 29 May 2010 19:24

> I'd suggest lookling at the file w/ the import wizard first; if it
> handles it, that's probably the least intensive from user standpoint.
>
> textscan() is more flexible than textread() Specifically, the
> 'collectoutputs' option will place the numerics in an array which is
> convenient for plotting.
>
> datenum() and friends works on cell arrays, too...
>
> --

Thank you once again for your response, dpb; this is greatly
appreciated. The import wizard seems to handle the file correctly, and
in Matlab R2010a, I'm also given the ability to generate code to load
the file:

fileToRead = 'test.csv';
DELIMITER = ',';
HEADERLINES = 3;

% Import the file
newData = importdata(fileToRead, DELIMITER, HEADERLINES);

% Create new variables in the base workspace from those fields.
vars = fieldnames(newData);
for i = 1:length(vars)
assignin('base', vars{i}, newData.(vars{i}));
end

This code creates the following in the workspace:

DELIMITER, HEADERLINES, data, fileToRead, i, newData, textdata, vars

Note that "textdata" is not listed in the code, but Matlab creates this
variable in the workspace.


>> size(textdata)

ans =

6840 72

Then how would I deal with the "NAN" elements in "textdata" and convert
the cell array to numerical values? Suppose that I want to grab the
first and 66th column of this cell array, remove the "NAN" elements, and
then convert the matrix all to a value such as double?

However, this has given me yet another idea. Perhaps I could write a
MEX file in C. The MEX program would parse the data as I please and
then return it to Matlab. To me, this seems much easier than trying to
work with all of these cell arrays.

Nicholas

From: Nicholas Kinar on 29 May 2010 19:27

>
> By explaining what the problem is? This is a fairly trivial
> exercise...
>
> Rune

Perhaps trivial to you, Rune; I've been using either Fortran/C/C++ for a
long time, but you know more of Matlab than I do at this time.

Nicholas
From: Nicholas Kinar on 29 May 2010 19:36

>
> Then how would I deal with the "NAN" elements in "textdata" and convert
> the cell array to numerical values? Suppose that I want to grab the
> first and 66th column of this cell array, remove the "NAN" elements, and
> then convert the matrix all to a value such as double?

Perhaps "remove" is not the right operation. I might want to convert
"NAN" to "NaN" so that Matlab can still plot the data.

Nicholas
From: TideMan on 29 May 2010 21:50
On May 30, 11:27 am, Nicholas Kinar <n.ki...(a)usask.ca> wrote:
> > By explaining what the problem is? This is a fairly trivial
> > exercise...
>
> > Rune
>
> Perhaps trivial to you, Rune; I've been using either Fortran/C/C++ for a
> long time, but you know more of Matlab than I do at this time.
>
> Nicholas

Oh dear, now you've torn it.
Mentioning Fortran and Rune in the same sentence is like pouring
gasoline on a fire...................

From: dpb on 29 May 2010 21:48
Nicholas Kinar wrote:
>
>>
>> Then how would I deal with the "NAN" elements in "textdata" and convert
>> the cell array to numerical values? Suppose that I want to grab the
>> first and 66th column of this cell array, remove the "NAN" elements, and
>> then convert the matrix all to a value such as double?
>
> Perhaps "remove" is not the right operation. I might want to convert
> "NAN" to "NaN" so that Matlab can still plot the data.

Oh, the "NAN" is embedded ASCII text; I assumed it was a NaN

To use cell arrays, you simply dereference them w/ the curly brackets or
if you need to convert to arrays unless later versions of Matlab (I'm at
a fairly old release now) need to use for loops in this version.

But, textscan() does have the 'group' option I mentioned earlier that
does place things in arrays of same type (but the mixed numeric/text is
an issue it won't handle well, that's true...

Not knowing precisely the data, something otoo the following trivial
example may help. Matlab isn't C or C++ so it takes a little while
getting used to, perhaps even more so if one is adept in another
language w/ so much to unlearn... :)

>> c(1)=num2cell(pi);
>> c(3)=num2cell(2);
>> c(2)=cellstr('NAN')
c =
[3.1416]
'NAN'
[ 2]
>> for idx=1:length(c), if isstr(c{idx}), c(idx)=num2cell(nan);end,end
>> c
c =
[3.1416]
[ NaN]
[ 2]

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