How to add Datetime to my time column in Matlab or Python

Question

I am currently working on constructing my dataset after extracting signals from a (.mat) database in Matlab.

[X,Y]=extract_structures(filename);

time=X(1).Data;

time =

Columns 1 through 6

         0    0.0100    0.0200    0.0300    0.0400    0.0500

  Columns 7 through 12

    0.0600    0.0700    0.0800    0.0900    0.1000    0.1100

 Columns 5 119 through 5 124

   51.1803   51.1903   51.2003   51.2103   51.2203   51.2303

  Columns 5 125 through 5 127

   51.2403   51.2503   51.2603

The X representing time. I extracted this time variable and other signals and constructed my data vector, starting with the first column as time, following this syntax :

data = [time' variable_u' variable_y'....... ];

To be able to use the csv file in Python my dataset should have a date column that contains the datetime of the time-series.

How can I achieve the transformation of the 'time' column into a datetime format using Matlab before exporting the csv file into Python.

Answer 1

We dont have the mat file so this is following a guess. My guess is that what you are reading is datenum results , and that you need to convert them to the full datetime info. this can be done in matlab using

 [y,mo,d,h,mi,s] = datevec(input)

in Python there is a little more complexity:

from datetime import datetime, timedelta

def matlab_datenum_to_datevec(datenum):
    # MATLAB's datenum starts on January 0, 0000 which is -366 days from January 1, 0001
    # Python's datetime starts from January 1, 1970
    # Therefore, we need to find the difference in days between these two start dates
    # and then add this to the provided datenum

    matlab_start = datetime(1, 1, 1)
    python_start = datetime(1970, 1, 1)
    days_difference = (python_start - matlab_start).days

    # Convert MATLAB datenum to Python datetime
    python_datetime = matlab_start + timedelta(days=datenum - days_difference)

    # Convert to date vector [year, month, day, hour, minute, second]
    date_vector = [python_datetime.year, python_datetime.month, python_datetime.day,
               python_datetime.hour, python_datetime.minute, python_datetime.second]

   return date_vector

an example using this:

datenum_value = 738427  # This is an example datenum value
date_vector = matlab_datenum_to_datevec(datenum_value)
print(date_vector)

This function matlab_datenum_to_datevec takes a MATLAB datenum value as input and returns a date vector similar to MATLAB's datevec output. The difference between the MATLAB and Python date systems is accounted for in the calculation.