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date and time string identification

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Jorge Luis Paredes Estacio
Edited: Stephen23 on 19 Dec 2022
Hello, I have the following information obtained from a text-file
date_hne: {'2014' '04' '01' '23' '46' '44.998300'}
date_hnn: {'2014' '04' '01' '23' '46' '44.998300'}
date_hnz: {'2014' '04' '01' '23' '46' '44.998300'}
as output in a cell array. I need to convert this information into a date vector that identify the date and time using the following command
formatIn = 'yyyy-MM-dd HH:mm:ss.SSS'
date_hne = datestr(date_hne,formatIn)
date_hnn = datestr(date_hnn,formatIn)
date_hnz = datestr(date_hnz,formatIn)
The seconds can be rounded as 45
The readable file is an compressed file (wwith 3 files) in order to be read. I can not attached the file that is why I attached as an uncompressed file here.
The script is as follows
%% Sub-function 5: this works for the data from the CENTRO SISMOLOGICO NACIONAL (CSN) OF CHILE
function [date_hne, date_hnn, date_hnz] = import_zip_chile (filename)
mkdir('tmp')
if strcmp(filename(end-2:end),'zip')==1
unzip(filename,'tmp');
else
error('Not a Zip');
end
cd('tmp')
content=dir;
content(1:2,:)=[];
cd ..
fname = content(1).name;
fname = fname(1:end-8);
formatIn = 'yyyy-MM-dd HH:mm:ss.SSS'
% S = dir(fullfile(path,[file_name,'*.txt']));
index_station = 0; %index added for stations
%% create list of unique filenames like 20211104-041752-C16O
% list of unique files :
% load "HNE"
try
file_name_1 = [fname, '-HNE.txt'];
file_name_1 = strrep(file_name_1,'_','-');
[header_hne] = import_from_CSN_chile(['tmp\',file_name_1],1);
catch
file_name_1 = [fname, '-HLE.txt'];
file_name_1 = strrep(file_name_1,'_','-');
[header_hne] = import_from_CSN_chile(['tmp\',file_name_1],1);
end
number_of_rows_header = min(size(header_hne));
for i=1:number_of_rows_header
if strcmp(header_hne(i,1:length('# Tiempo de Origen:')),'# Tiempo de Origen:')==1
line_date = i;
end
end
date_hne = regexp(header_hne(line_date,:),'-?\d+\.?\d*|-?\d*\.?\d+','match'); % date and time
%date_hne = join(date_hne);
date_hne = date_hne(~isspace(date_hne));
date_hne = erase(date_hne,"-"); %erase dash fromt the string
date_hne = datestr(date_hne); %added to convert to date string
% load "HNN"
try
file_name_2 = [fname, '-HNN.txt'];
file_name_2 = strrep(file_name_2,'_','-');
[header_hnn] = import_from_CSN_chile(['tmp\',file_name_2],1);
catch
file_name_2 = [fname, '-HLN.txt'];
file_name_2 = strrep(file_name_2,'_','-');
[header_hnn] = import_from_CSN_chile(['tmp\',file_name_2],1);
end
date_hnn = regexp(header_hnn(line_date,:),'-?\d+\.?\d*|-?\d*\.?\d+','match'); % date and time
%date_hnn = join(date_hnn);
date_hnn = date_hnn(~isspace(date_hnn));
date_hnn = erase(date_hnn,"-"); %erase dash fromt the string
date_hnn = datestr(date_hnn); %added to convert to date string
% load "HNZ"
try
file_name_3 = [fname, '-HNZ.txt'];
file_name_3 = strrep(file_name_3,'_','-');
[header_hnz] = import_from_CSN_chile(['tmp\',file_name_3],1);
catch
file_name_3 = [fname, '-HLZ.txt'];
file_name_3 = strrep(file_name_3,'_','-');
[header_hnz] = import_from_CSN_chile(['tmp\',file_name_3],1);
end
date_hnz = regexp(header_hnz(line_date,:),'-?\d+\.?\d*|-?\d*\.?\d+','match'); % date and time
%date_hnz = join(date_hnz);
date_hnz = date_hnz(~isspace(date_hnz));
date_hnz = erase(date_hnz,"-"); %erase dash fromt the string
date_hnz = datestr(date_hnz); %added to convert to date string
rmdir ('tmp','s')
end
%%function to import from chile
function [head] = import_from_CSN_chile(filename,nclm,skip,formt)
% READCLM Reads numerical data from a text file into a matrix.
% Text file can begin with a header or comment block.
% [DATA,HEAD] = READCLM(FILENAME,NCLM,SKIP,FORMAT)
% Opens file FILENAME, skips first several lines specified
% by SKIP number or beginning with comment '%'.
% Then reads next several lines into a string matrix HEAD
% until the first line with numerical data is encountered
% (that is until first non-empty output of SSCANF).
% Then reads the rest of the file into a numerical matrix
% DATA in a format FORMAT with number of columns equal
% to number of columns of the text file or specified by
% number NCLM. If data does not match the size of the
% matrix DATA, it is padded with NaN at the end.
%
% READCLM(FILENAME) reads data from a text file FILENAME,
% skipping only commented lines. It determines number of
% columns by the length of the first data line and uses
% the floating point format '%g';
%
% READCLM uses FGETS to read the first lines and FSCANF
% for reading data.
% Defaults and parameters ..............................
formt_dflt = '%g'; % Default format for fscanf
addn = nan; % Number to fill the end if necessary
% Handle input ..........................................
if nargin<1, error(' File name is undefined'); end
if nargin<4, formt = formt_dflt; end
if nargin<3, skip = 0; end
if nargin<2, nclm = 0; end
if isempty(nclm), nclm = 0; end
if isempty(skip), skip = 0; end
% Open file ............................
[fid,msg] = fopen(filename);
if fid<0, disp(msg), return, end
% Find header and first data line ......................
is_head = 1;
jl = 0;
head = ' ';
while is_head % Add lines to header.....
s = fgets(fid); % Get next line
jl = jl+1;
is_skip = jl<=skip;
is_skip = jl<=skip | s(1)=='%';
out1 = sscanf(s,formt); % Try to read this line
% If unreadable by SSCANF or skip, add to header
is_head = isempty(out1) | is_skip;
if is_head & ~is_skip
head = str2mat(head,s(1:length(s)-1)); end
end
head = head(2:size(head,1),:);
% Determine number of columns if not specified
out1 = out1(:)';
l1 = length(out1);
if ~nclm, nclm = l1; end
fclose (fid); % Close file ..........
end
  1 Comment
Stephen23
Stephen23 on 19 Dec 2022
Edited: Stephen23 on 19 Dec 2022
It is unclear what your actual question is.
This is very smelly code:
cd('tmp')
content=dir;
content(1:2,:)=[];
cd ..
Do not use CD just to access data files or call DIR. Using CD is slow and makes debugging harder. You should use absolute/relative filepaths.
Deleting elements 1 & 2 from the structure returned by DIR() is a buggy way to handle the dot directory names:
As Walter Roberson wrote in that last link: "In short: if your code assumes that '.' and '..' are the first two entries in a directory, your code has a bug (even in MS Windows). If your code assumes that directory entries are returned in any sorted order, your code has a bug (in all OS.)"
The robust approach is one of these:
  • use ISMEMBER, SETDIFF, or similar on the names.
  • specify the DIR() match string to exclude dot directory names.

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Answers (1)

Peter Perkins
Peter Perkins on 19 Dec 2022
Edited: Peter Perkins on 19 Dec 2022
"I have the following information obtained from a text-file
date_hne: {'2014' '04' '01' '23' '46' '44.998300'}"
I don't see anything even remotely like that in the three text files you've attached. And that's not a great format to end up with. post more information on how you got there, and people can probably help.
Also: these two things
formatIn = 'yyyy-MM-dd HH:mm:ss.SSS'
date_hne = datestr(date_hne,formatIn)
are incompatible. The first is a datetime format. The second is a call to the legacy datestr function, which uses a very different set of formats. Don't use datestr.

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