Thread Subject: read data in Matlab

Suppose I have a data file:

ID C1 C2 ... C1000
R1 # # #
R2 # # #
.
.
.
R2000 # # #

How can I read it into three variables: ColID, RowID, and
1 2000x1000 matrix of numerical values? textscan or
textread seems to need a format specifier for each column
which is troublesome for large number of columns.

Also if the file is too big and I only need to read in
certain rows (for example, only read in R2, R28, R34,...),
then how can I do this?

Any solution or hints? Thanks very much.

Jerry wrote:
> Suppose I have a data file:
>
> ID C1 C2 ... C1000
> R1 # # #
> R2 # # #
> .
> .
> .
> R2000 # # #

> How can I read it into three variables: ColID, RowID, and
> 1 2000x1000 matrix of numerical values? textscan or
> textread seems to need a format specifier for each column
> which is troublesome for large number of columns.

Compute the format instead of writing it by hand.

hfmt = ['%*s', repmat('%s', 1, 1000), '\n'];
nfmt = ['%s', repmat('%f', 1, 1000), '\n'];

Then textscan(fid, hfmt, 1, 'CollectOutput', 1)
to read the column headers.
textscan(fid, nfmt, 'CollectOutput', 1)
to read the row headers and numeric values

> Also if the file is too big and I only need to read in
> certain rows (for example, only read in R2, R28, R34,...),
> then how can I do this?

textscan() one row at a time, with 'Headerlines' set to the number of
rows to skip -- e.g., Headerlines 25 after reading R2. You will
need to do your own work to store each line result -- that is, there
is no facility to say "read only these specified lines and put
everything read into appropriate cell arrays"

--
Q = quotation(rand);
if isempty(Q); error('Quotation server filesystem problems')
else sprintf('%s',Q), end