Extracting specific repeating lines of text after a heading using fgetl and textscan

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Vincent Scalfani
Vincent Scalfani 2016-7-19
评论： Vincent Scalfani 2016-7-21
Here is an example of the data I am working with. I would like to extract the line directly following each KEY tag. The files have many thousands of these, so I need to create a loop with textscan or something similar.
> <NAME>
mary
> <AGE>
30
> <KEY>
RDHQFKQIGNG
> <NAME>
john
> <AGE>
56
> <KEY>
JFJNNFNFKFNN
Desired result:
RDHQFKQIGNG
JFJNNFNFKFNN
Here is where I am at (adapted from a similar question in the past), the code does not seem to be moving the cursor, and instead works for the first one, and then grabs all data after it, instead of just the data following the KEY line.
f = fopen('data.txt', 'rt');
tline = fgetl(f);
while isempty(strfind(tline, '> <KEY>'))
if tline == -1
break;
end
line = fgetl(f);
end
if tline ~= -1
data = textscan(f,'%s','Delimiter','\r\n');
else
disp('not found');
end
fclose(f);
Thanks!

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采纳的回答

Stephen23
Stephen23 2016-7-19
>> str = fileread('temp1.txt');
>> C = regexp(str,'(?<=> <KEY>\s+)\S+','match')
C =
'RDHQFKQIGNG' 'JFJNNFNFKFNN'
Tested on this file:
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Stephen23
Stephen23 2016-7-20
Try this:
E = regexp(str,'^> <KEY>\s+\S+','match','lineanchors');
E = strtrim(strrep(E,'> <KEY>',''));
And have a play with this script:
Vincent Scalfani
Vincent Scalfani 2016-7-21
Amazing!!! PERFECT. It took 1 second to process over 4 million lines of text. Thanks so much for your time.

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