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Stephen
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Possible to regexp a file with a for loop using expressions from an array?

Asked by Stephen
on 4 Jul 2019
Latest activity Answered by Stephen
on 5 Jul 2019
I have a text file that I am pulling hex values from using regexp:
returned = string(regexp( filetext, '(?<=xyz address 0x)[0-9a-fA-F]+' , 'match' ));
if ~isempty(returned)
xyzHex = sscanf(returned,'%x');
fprintf ('xyx = %08x \n',xyzHex);
end
(I understand this may be clunky, but I've only just started with MatLab)
What I would like to do is create an array which contains all the expressions I would like to search for, and a single for loop which will iterate though the array, and process the hex value (eg printing). The idea being that adding will only require the addition of the expression to the array.
Is this possible?

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Any of the arguments to regexp can be string variables, yes.

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R2019a

2 Answers

Answer by per isakson
on 4 Jul 2019
Edited by per isakson
on 5 Jul 2019

I'm not sure that I fully understand your question. However, try this script %%-section by section
%%
txt = fileread( 'cssm.txt' );
%%
cac = regexp( txt, '(\w+) address 0x([0-9a-fA-F]{8})', 'tokens' );
%% black magic
cac = cat( 1, cac{:} );
sas = cell2struct( cac(:,2), cac(:,1) );
%%
for f = reshape( fields( sas ), 1,[] )
xyzHex = sscanf(sas.(f{1}),'%x');
fprintf( '%s = %x \n', f{1}, xyzHex );
end
where cssm.txt contains
any text xyz address 0x12345678 more text
any text xy1 address 0x12345678AB more text
any text xy2 address 0x90ABCDEF more text
any text xy3 address 0x90abcdef more text
The struct sas
>> sas
sas =
struct with fields:
xyz: '12345678'
xy1: '12345678'
xy2: '90ABCDEF'
xy3: '90abcdef'
>>
The script outputs
xyz = 12345678
xy1 = 12345678
xy2 = 90abcdef
xy3 = 90abcdef
>>

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Answer by Stephen
on 5 Jul 2019

Thanks, this looks interesting and I can definitley learn from it.
I'm not certain it wil work in this particular application, as there will be many hex adresses in my file and I only want to pull certain ones, eg. xyz and xy2 but not any others. The ones I want will be added to the array.
I think I have a solution, and if it works I'll share it here, but I found it wasn't working because some of my "xyz" strings have square brackets in them and need to be escaped in the regexp expression, but not in the fprintf :/

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