Data extraction from .txt file
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Mate 2u
el 31 de Mzo. de 2012
Respondida: D. Ali
el 27 de Abr. de 2019
I have a LARGE minute data set in the format of:
10/21/2002,0601,0.97360,0.97360,0.97360,0.97360,0,0
10/21/2002,0602,0.97360,0.97360,0.97360,0.97360,0,0
10/21/2002,0603,0.97350,0.97350,0.97340,0.97350,0,0
10/21/2002,0604,0.97340,0.97340,0.97340,0.97340,0,0
10/21/2002,0605,0.97330,0.97330,0.97330,0.97330,0,0
10/21/2002,0606,0.97300,0.97310,0.97300,0.97310,0,0
10/21/2002,0607,0.97290,0.97290,0.97290,0.97290,0,0
10/21/2002,0608,0.97280,0.97280,0.97260,0.97260,0,0
10/21/2002,0609,0.97270,0.97270,0.97260,0.97260,0,0
This goes on till 2012.
I need two programs:
- Select a time period for which I need. So lets say 0600-0630, then the program would store IN ORDER all the 0600-0630 in one matrix in matlab.
- Select selected dates period and time period. So lets say I want 10/21/2002 0500 - 0700 and 17/21/2002 - 0500 - 0700.
Basically I want programs which will let me extract any time period and date period from the data. It is huge data so remember the program cant run for too long.
Look forward to some replies. Thanks in advance.
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Respuesta aceptada
per isakson
el 1 de Abr. de 2012
Check whether this approach is fast enough. SSCANF used to be faster than DATEVEC to convert date strings with identical format for all lines and only numbers. Might not be the case anymore.
I copied your data to cssm.dat.
fid = fopen( '.\cssm.dat', 'r' );
cac = textscan( fid, '%s%s%f%f%f%f%f%f', 'Delimiter', ',' );
sts = fclose( fid );
vec = zeros( numel( cac{1,1} ), 6 );
[ vec(:,1), vec(:,2), vec(:,3), ~, ~, ~ ] = datevec( cac{1,1}, 'mm/dd/yyyy' );
[ ~, ~, ~, vec(:,4), vec(:,5), ~ ] = datevec( cac{1,2}, 'HHMM' );
dat = [cac{1,3:end}];
m1 = 4;
m2 = 7;
d06 = dat( vec(:,4)==6 & vec(:,5)>=m1 & vec(:,5)<=m2, : );
v06 = vec( vec(:,4)==6 & vec(:,5)>=m1 & vec(:,5)<=m2, : );
Use the same approach for your second case.
Rounding errors should not be a problem in this example since DATEVEC returns flint (floating integers)
FSCANF (with 64bit R2011a) seems to be twice(?) as fast
fid = fopen( '.\cssm.dat', 'r' );
num = fscanf( fid, '%2u/%2u/%4u,%2u%2u,%f,%f,%f,%f,%f,%f', [11,inf] );
sts = fclose( fid );
num = transpose( num );
vec(:,1:5) = num(:,[3,2,1,4,5]);
vec(:,6) = 0;
dat = num(:,6:end);
However, this requires a bit more care and a file that adheres to the format.
The code above assumes that all data fits in memory.
Surprisingly, the code below is another 20% faster (with 64bit R2011a). I see three advantages with this code. Easy to handle header lines. Easier do debug when the text file is "corrupted". One additional line of code will handle comma as decimal separator. And it's a bit faster.
fid = fopen( '.\cssm.dat', 'r' );
cac = textscan( fid, '%s', 'Whitespace','', 'Delimiter','\n' );
sts = fclose( fid );
str = transpose( char( cac{:} ) );
str = cat( 1, str, repmat( ',', 1, size(str,2) ) );
num = sscanf( str, '%2u/%2u/%4u,%2u%2u,%f,%f,%f,%f,%f,%f,', [11,inf] );
vec(:,1:5) = num(:,[3,2,1,4,5]);
vec(:,6) = 0;
dat = num(:,6:end);
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Más respuestas (4)
per isakson
el 4 de Abr. de 2012
isMonday = ( weekday( datenum( vec ) ) == 2 ); % every monday
However, bank holidays is a problem. As far as I know Matlab doesn't have a calendar. I guess there is a Finacial Toolbox, which has a calendar.
Bank holidays varies between countries. Google finds e.g: https://www.gov.uk/bank-holidays
=====
Kevin Lamb
el 30 de Oct. de 2015
Editada: Kevin Lamb
el 10 de Nov. de 2015
so I was presented with a few dozen log files that were not uniform in size or structure, or quantity of tests ran that was in the form of:
header header blah
header
beginning of first repetition of datalog
blah blah number blah blah number
blah blah blah
blah blah blah blah
number you want is: 50 second number you want is: 100 bla bla bla
blah blah blah
end of first repetition of data log
beginning of second repetition of datalog
... so on
my solution was as follows;
%directory
file_names = dir('C:\Work\...\matlab\Log_Folder');
file_names = {file_names.name};
for index2 = 3:1:length(file_names)
%find file, offset by 2
fileID = fopen(char(file_names(index2)),'r');
%parse data
logfile = textscan(fileID, '%s','Delimiter','\n','MultipleDelimsAsOne',1);
Parse1 = strfind(logfile{:},'number you want is');
Parse2 = find(not(cellfun('isempty',Parse1)));
Parse3 = logfile{1}(Parse2);
for index1 = 1:1:length(Parse3)
Parse4(:,index1) = textscan(Parse3{index1},'%s %s %s %s %f %s %s %s %s %s %f %s %s %s', 'Delimiter', ' ', 'MultipleDelimsAsOne',1)';
end
%allocate data to output
finaldataparse(index2-2,:) = {[Parse4{11,:}]'};
clear Parse1 Parse2 Parse3 Parse4
end
What this code ultimately ended up doing was incrementing through numerous log files, allocating every line of the log file to a cell, then looking at each cell for that keyphrase, "number you want is". Once found, it broke up those cells by the second textscan call to extract the numbers of interest, from there it was fairly easy to put it in a usable form and do data analysis.
With the uniform data file you have, using collectoutput would probably be useful.
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D. Ali
el 27 de Abr. de 2019
I have similar question where I need to extarct all MCAP amples with time they occured on in separat file and plot if possilbe
I attached the file
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