Pulling out a number and a date + time from text file after specific lines

Question

Heidi Mäkitalo 2019-6-27

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/469172-pulling-out-a-number-and-a-date-time-from-text-file-after-specific-lines

编辑： Heidi Mäkitalo 2019-7-2

采纳的回答： Bob Thompson

在 MATLAB Online 中打开

Hello all,

I have the following two lines in my text file:

Time of Interval 0:  03/03/18  18:14:02
Interval: 0.02 sec

First off, how can I pull out the number after "Interval:" ?

Secondly, how can I do the same for the date and time after "Time of Interval 0:" ?

The number and the date vary from file to file, but the text preceding them is always the same. I need a solution that works in every situation.

Thanks in advance!

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Answer 1

Bob Thompson 2019-6-27

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/469172-pulling-out-a-number-and-a-date-time-from-text-file-after-specific-lines#answer_381059

The most reliable way that I know of to get this is by using fgetl.

file = fopen('mytextfile.txt'); % Access the file
line = fgetl(file);             % Read first line
c = 1;                          % Record the line number for debugging purposes
while ~isnumeric(line) & ~strcmp(line(1:16),'Time of Interval') % Check for desired line, or end of file
    line = fgetl(file);         % Read next line
    c = c + 1;                  % Advance line count
end
parts = strsplit(line,': ');
number = str2num(parts{1}(18:end));
dt = datetime(parts{2});

There may be some thing syou need to tweak to make it personalized to your inputs, but that should work.

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Heidi Mäkitalo 2019-7-2

编辑：Heidi Mäkitalo 2019-7-2

在 MATLAB Online 中打开

For some reason Matlab complained about matrix dimensions being exceeded when I tried to use your code, don't know what that was about. This is how I ended up doing it:

Zero interval

function zinterval = FindZeroInterval(file)
    opened_file = fopen(file,'rt');
    zinterval = '';
    while ~strncmpi(zinterval,'Time of Interval 0',18)
        zinterval = fgetl(opened_file);
    end
    zinterval = datetime(zinterval(20:end), 'InputFormat','MM/dd/yy HH:mm:ss');
    
end

which gives

zinterval = 
datetime
03-Mar-2018 18:14:02

and interval

function interval = FindInterval(file)
    opened_file = fopen(file,'rt');
    
    interval = '';
    while ~strncmpi(interval,'Interval:',8)
        interval = fgetl(opened_file);
    end
    interval = str2double(regexp(interval,'\d+[\.]?\d*','match','once'));
    
end