MATLAB datenum日期转换为Python日期

目录

• 摘要
• 示例1：小时制，基准年份1800-1-1
• 示例2：一天制，基准年份1800-1-1
• 示例3：时间列表转换
• 截图（参考）
• 参考

摘要

MATLAB datenum时间格式参数众多，本文只简单关注 units 参数，即基准年份和计时度量（天、小时）。

命令行演示在 ipython 和 Octave 中进行。

示例1：小时制，基准年份1800-1-1

Time Attributes:
units
= 'hours since 1800-1-1 00:00:0.0'
long_name
= 'Time'
axis
= 'T'
standard_name
= 'time'
coordinate_defines = 'start'
delta_t
= '0000-00-01 00:00:00'
actual_range
= [1.74e+06 1.75e+06]
avg_period
= '0000-00-01 00:00:00'
time(1:5):
1744392
1744416
1744440
1744464
1744488
#来源： 参考1
# python
import numpy as np
origin = np.datetime64('1800-01-01', 'D')
date1 = 1744392/24 * np.timedelta64(1, 'D') + origin
# '1999-01-01'

示例2：一天制，基准年份1800-1-1

time {
String units "days since 1800-1-1 00:00:00";
String long_name "Time";
Float64 actual_range 19723.00000000000, 76214.00000000000;
String delta_t "0000-01-00 00:00:00";
String avg_period "0000-01-00 00:00:00";
String prev_avg_period "0000-00-07 00:00:00";
String standard_name "time";
String axis "t";
}
#来源： 参考2
# python
import numpy as np
origin = np.datetime64('1800-01-01', 'D')
date2 = 19723 * np.timedelta64(1, 'D') + origin
# '1854-01-01'

示例3：时间列表转换

import numpy as np
import pandas as pd
datenums = np.array([730990, 733301, 729159,
734471, 736858, 731204]) # 来源：参考7
timestamps = pd.to_datetime(datenums-719529, unit='D')
'''
DatetimeIndex(['2001-05-19', '2007-09-16', '1996-05-14',
'2010-11-29', '2017-06-12', '2001-12-19'],
dtype='datetime64[ns]', freq=None)
'''

截图（参考）

验证：

参考

1. convert narr model data time to datevec or datestr https://ww2.mathworks.cn/matlabcentral/answers/141304-convert-narr-model-data-time-to-datevec-or-datestr
2. OPeNDAP-某数据集格式：http://test.opendap.org/dap/data/nc/sst.mnmean.nc.gz.das
3. Python datetime to Matlab datenum https://stackoverflow.com/questions/8776414/python-datetime-to-matlab-datenum
4. Converting Matlab's datenum format to Python https://stackoverflow.com/questions/13965740/converting-matlabs-datenum-format-to-python/36249553
5. [Tutor] datenum https://mail.python.org/pipermail/tutor/2003-September/025454.html
6. 在日期时间数组、数值和文本之间转换 https://ww2.mathworks.cn/help/matlab/matlab_prog/convert-between-datetime-arrays-numbers-and-strings.html
7. datenum用法 https://ww2.mathworks.cn/help/matlab/ref/datenum.html
8. 日期和时间 https://ww2.mathworks.cn/help/matlab/date-and-time-operations.html?s_tid=CRUX_lftnav