Math Forum Discussions

Geoff Hazel

Posts: 8
Registered: 12/7/04

Load Numbered Files.
Posted: Jul 25, 1996 11:48 AM

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Hello,

I complained yesterday about it being hard to load a bunch of ASCII data
files. Here's the function I wrote to solve my immediate problem:
numbered files. Hope someone finds it useful.

Geoff Hazel
NRL
geoff.hazel@nrl.navy.mil

PS Thanks to those who responded to yesterday's gripe with suggestions.

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function out = loadnumf(pre, nums, post, ext)
%LOADNUMF Load numbered ASCII data files into a matrix.
% Loads single-column ASCII data files with numerals in their names
% into a matrix using 'load'. An arbitrary list of numbers can be
% specified with letters before and/or after, and a filename
% extension. NOTE: The filename extension should include a '.' if
% one is desired. The function should work if the filenames lack
% extensions ('-ascii' added to 'load' command). If 'nums' is a
% matrix, the files are a loaded in column order.
%
% I/O fomat is : out = loadnumf(pre, nums, post, ext)
% where:
% out = Resulting matrix with data files in columns.
% pre = String containing any letters preceding the numerals.
% nums = List of numbers corresponding to numbered files to load.
% post = String containing any letters following the numerals.
% ext = String containing filename extension (including '.').

% GGHazel 7/24/96

% Check args for sanity
if nargin ~= 4
error('I Expect 4 input aruments.');
end

if ~isstr(pre) | ~isstr(post) | ~isstr(ext)
error('Input args not strings.');
end

if isempty(nums)
error('Empty numbers argument.');
end

% Figure out number of files, and reshaps 'nums' if necessary
[m, n] = size(nums);
if n ~=1 & m ~=1
nums = reshape(nums,1,m*n);
end
n = n*m;

% Do the work
for m = 1:n
varname = [pre,int2str(nums(m)),post]; % name of 'load's output var.
command = ['load ', varname, ext]; % The 'load' command.
if isempty(ext)
command = [command, ' -ascii']; % Deal with extentionless names.
end
if ~exist([varname, ext]) % See if file exists.
msg = ['Can''t find file: ', varname, ext];
error(msg);
end
eval(command); % Load the file
eval(['out(:,m) = ', varname,';']); % Append it to output matrix
eval(['clear ', varname]); % Save memory
end

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