Find strings within other strings then pull data from that point
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dear collegaes, please let me ask your help to find a solution for my data analisys.
I have a P0300.txt file that contains a long strip.
here is a portion of P0300.txt:
59 04 03 01 00 65 01 3E 51 09 00 00 51 1C 00 E1
I need to find sets of data, sets could be 2 or 4 digits.
lets say I need to find 01 3E
DATA = regexp(fileread('P0300.txt'), '\r?\n', 'split')';
>> A = string(DATA);
>> B = strfind(A,'01 3E');
B gives me the position where 01 3E is, in this case B = 19
after this I need to extract the 6 digits on the rigth 51 09 00 <-- this values can change depend on test conditions
Any idea on how can I do that?
your feedback will be highly appreciated
采纳的回答
filename = 'P0300.txt';
to_find = '01 3E';
str = fileread(filename);
pat = strjoin(repmat({'[\dA-F]{2}'},1,3),' ');
C = regexp(str,[to_find ' (' pat ')'],'tokens');
C = [C{:}]
10 个评论
A-Rod
2024-8-19
Voss
2024-8-19
You're welcome!
A-Rod
2024-8-19
Sure, no problem:
filename = 'P0300.txt';
% now to_find is a cell array with two columns; the first column is
% the character vector to find, and the second column is the number
% of digits to grab afterward (the number of digits must be even)
to_find = { ...
'E1 54', 6; ...
'01 3E', 4; ...
};
str = fileread(filename);
N = size(to_find,1);
results = cell(N,1);
for ii = 1:N
pat = strjoin(repmat({'[\dA-F]{2}'},1,to_find{ii,2}/2),' ');
C = regexp(str,[to_find{ii,1} ' (' pat ')'],'tokens');
results{ii} = [C{:}];
end
results
results{1}
results{2}
A-Rod
2024-8-19
Voss
2024-8-19
You're welcome!
So you want to split up a two-digit sequence in that case and just grab the first digit? If so, see the modfied code below:
filename = 'P0300.txt';
% now to_find is a cell array with two columns; the first column is
% the character vector to find, and the second column is the number
% of digits to grab afterward
to_find = { ...
'E1 54', 3; ...
'01 3E', 5; ...
'51 09', 4; ...
};
str = fileread(filename);
N = size(to_find,1);
results = cell(N,1);
for ii = 1:N
n = to_find{ii,2};
pat = strjoin(repmat({'[\dA-F]{2}'},1,floor(n/2)),' ');
if rem(n,2)
pat = [pat ' [\dA-F]'];
end
C = regexp(str,[to_find{ii,1} ' (' pat ')'],'tokens');
results{ii} = [C{:}];
end
results{:}
Voss
2024-8-20
You're welcome!
更多回答（2 个）
To extract 6 digits following a specific pattern in your text file, you can utilize MATLAB's string manupilation functions such as 'regexp'.
Here is a sample MATLAB script to achieve the same:
fileContent = fileread('P0300.txt');
pattern = '01 3E';
% Use regular expression to find the pattern and extract the following 6 digits
expression = [pattern, '\s+([\dA-F]{2}\s+[\dA-F]{2}\s+[\dA-F]{2})'];
match = regexp(fileContent, expression, 'tokens');
% Check if any match is found
if ~isempty(match)
% Extract the first match (if multiple matches are found)
extractedDigits = match{1}{1};
fprintf('Extracted digits: %s\n', extractedDigits);
else
fprintf('Pattern not found in the file.\n');
end
You can refer the following MathWorks documentation for more information:
fileContent = fileread('P0300.txt');
prefix="01 3E";
e=" "+digitsPattern(2);
pattern = prefix+e+e+e;
matches = extractAfter( extract(fileContent,pattern), prefix);
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