How to read and process a text file?
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I have attached a sample text file. As yOu can see the comment lines starting with $ must be ommited and the values alone must be read and assigned as variables. For the 'ID' set each column must be named separately like a1 to a4 for the second column and b1 to b4 for the third and so on. Similarly the 'NEXT' set must also be named as each column separately. Please help......
2 Comments
Walter Roberson
on 15 Dec 2019
Don't do that. Put all of the data into the same variable. Use a structure with dynamic field names for the main variable and use vectors instead of a1 a2 and so on.
Answers (1)
Walter Roberson
on 16 Dec 2019
S = fileread('sample.txt');
S = regexprep(S, {'^\$.*?\n', '\r'}, {'', ''}, 'lineanchors');
all_ids = string(regexp(S, '^\S*', 'match', 'lineanchors'));
noids = regexprep(S, '^\S*\s*', '', 'lineanchors');
mask = all_ids(1:end-1) ~= all_ids(2:end);
stops = find([mask true]);
eol_pos = regexp(noids, '.$', 'lineanchors');
block_lengths = diff([0, eol_pos(stops)]);
blocks_text = mat2cell(noids, 1, block_lengths);
ids = all_ids(stops);
values = cellfun(@(B) cell2mat(textscan(B, '', 'CollectOutput', true)), blocks', 'uniform', 0);
At this point, ids contains a string vector of the names such as NEXT, and values is a cell array of numeric arrays, with each entry containing the numeric data corresponding.
9 Comments
Walter Roberson
on 20 Dec 2019
Again, why do you need to name the columns when you can just index instead?
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