MATLAB Answers


How to load text file to workspace variables?

Asked by Tom Karlsson on 25 Oct 2019
Latest activity Commented on by Stephen Cobeldick on 27 Oct 2019
I wonder how to read/load variables from text file to matlab, with following format:
var1 val1
var2 val2
var3 val3
var4 val4
I want them to be loaded to workspace as variables with string name in var and numeric value as val.


on 26 Oct 2019
In general, that's a bad idea -- use MATLAB array syntax instead.
Use indexing.
Indexing is neat, simple to debug, and very efficient (unlike what you are trying to do).

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1 Answer

Answer by per isakson
on 26 Oct 2019
Edited by per isakson
on 26 Oct 2019

"load to workspace as variables with string name in var and numeric value as val." There need to be a really good reason to do that, because it comes at a cost. Read Why Variables Should Not Be Named Dynamically and then read Magically Making Variables Appear in a Workspace is Risky a second time.
After reading try
which outputs
Name Size Bytes Class Attributes
S 1x1 736 struct
var1 1x1 8 double
var2 1x1 8 double
var3 1x1 8 double
var4 1x1 8 double
where (in one m-file named cssm.m)
fid = fopen( 'cssm.txt' );
cac = textscan( fid, '%s%f' );
fclose( fid );
for jj = 1 : length(cac{1})
S.( cac{1}{jj} ) = cac{2}(jj); % dynamic names in a structure
assign( cac{1}{jj}, cac{2}(jj) ) % magically "poof" variables
whos S v*
function assign( name, val )
assignin( 'caller', name, val );
and where cssm.txt contains
var1 1
var2 2
var3 3
var4 4
Finally, are there any good reasons not to use "dynamic names in a structure" ?

  1 Comment

A table would also be a good choice.

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