How to use cftime - 10 common examples
To help you get started, we’ve selected a few cftime examples, based on popular ways it is used in public projects.
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pydata / xarray / xarray / coding / cftime_offsets.py View on Github 
delta_year = (date.month + months) // 12
month = (date.month + months) % 12
if month == 0:
month = 12
delta_year = delta_year - 1
year = date.year + delta_year
if day_option == "start":
day = 1
elif day_option == "end":
reference = type(date)(year, month, 1)
day = _days_in_month(reference)
else:
raise ValueError(day_option)
if LooseVersion(cftime.__version__) < LooseVersion("1.0.4"):
# dayofwk=-1 is required to update the dayofwk and dayofyr attributes of
# the returned date object in versions of cftime between 1.0.2 and
# 1.0.3.4. It can be removed for versions of cftime greater than
# 1.0.3.4.
return date.replace(year=year, month=month, day=day, dayofwk=-1)
else:
return date.replace(year=year, month=month, day=day)def test_num2date_hour_units(calendar, unit, shape, dtype):
date_type = _EXPECTED_DATE_TYPES[calendar]
expected = np.array([date_type(2000, 1, 1, 1, 0, 0, 0),
date_type(2000, 1, 1, 2, 0, 0, 0),
date_type(2000, 1, 1, 3, 0, 0, 0),
date_type(2000, 1, 1, 4, 0, 0, 0)]).reshape(shape)
numeric_times = np.array([1, 2, 3, 4]).reshape(shape).astype(dtype)
units = "{} since 2000-01-01".format(unit)
result = num2date(numeric_times, units=units, calendar=calendar)
np.testing.assert_equal(result, expected)d = datetime.strptime('2018-01-23 09:27:10.950000',"%Y-%m-%d %H:%M:%S.%f")
units = 'seconds since 2018-01-23 09:31:42.94'
assert(cftime.date2num(d, units) == -271.99)
# issue 143 - same answer for arrays vs scalars.
units = 'seconds since 1970-01-01 00:00:00'
times_in = [1261440000.0, 1261440001.0, 1261440002.0, 1261440003.0,
1261440004.0, 1261440005.0]
times_out1 = cftime.num2date(times_in, units)
times_out2 = []
for time_in in times_in:
times_out2.append(cftime.num2date(time_in, units))
dates1 = [str(d) for d in times_out1]
dates2 = [str(d) for d in times_out2]
assert(dates1 == dates2)
# issue #143 formatting of microseconds
d = cftime.num2date(1261440000.015625,units)
# on windows only 100 ms precision
assert(str(d)[0:24] == '2009-12-22 00:00:00.0156')
# issue #152 add isoformat()
assert(d.isoformat()[0:24] == '2009-12-22T00:00:00.0156')
assert(d.isoformat(sep=' ')[0:24] == '2009-12-22 00:00:00.0156')
assert(d.isoformat(sep=' ',timespec='milliseconds') == '2009-12-22 00:00:00.015')
assert(d.isoformat(sep=' ',timespec='seconds') == '2009-12-22 00:00:00')
assert(d.isoformat(sep=' ',timespec='minutes') == '2009-12-22 00:00')
assert(d.isoformat(sep=' ',timespec='hours') == '2009-12-22 00')
# issue #165: make sure python datetime returned
d=num2date(0,units="seconds since 2000-01-01 00:00:00",only_use_cftime_datetimes=False)
assert isinstance(d, datetime)
# issue #169: cftime.datetime has no calendar attribute, causing dayofwk,dayofyr methods
# to fail.
c = cftime.datetime(*cftime._parse_date('7480-01-01 00:00:00'))
assert(c.strftime() == '7480-01-01 00:00:00')err = np.abs(mins1 - mins2)
maxerr = max(err,maxerr)
assert(err < eps)
assert(date1.strftime(dateformat) == date2.strftime(dateformat))
if verbose:
print('calendar = %s max abs err (mins) = %s eps = %s' % \
(calendar,maxerr,eps))
eps = 1.e-6
units = 'hours since 0001-01-30 01:01:01'
hrs1 = date2num(dateref,units,calendar=calendar)
maxerr = 0.
for n in range(ntimes):
hrs1 += 0.001
date1 = num2date(hrs1, units, calendar=calendar)
hrs2 = date2num(date1, units, calendar=calendar)
date2 = num2date(hrs2, units, calendar=calendar)
err = np.abs(hrs1 - hrs2)
maxerr = max(err,maxerr)
assert(err < eps)
assert(date1.strftime(dateformat) == date2.strftime(dateformat))
if verbose:
print('calendar = %s max abs err (hours) = %s eps = %s' % \
(calendar,maxerr,eps))
eps = 1.e-8
units = 'days since 0001-01-30 01:01:01'
days1 = date2num(dateref,units,calendar=calendar)
maxerr = 0.
for n in range(ntimes):
days1 += 0.00001
date1 = num2date(days1, units, calendar=calendar)
days2 = date2num(date1, units, calendar=calendar)
date2 = num2date(days2, units, calendar=calendar)# also tests error found in issue #349
calendars=['standard', 'gregorian', 'proleptic_gregorian', 'noleap', 'julian',\
'all_leap', '365_day', '366_day', '360_day']
dateref = datetime(2015,2,28,12)
ntimes = 1001
verbose = True # print out max error diagnostics
for calendar in calendars:
eps = 100.
units = 'microseconds since 2000-01-30 01:01:01'
microsecs1 = date2num(dateref,units,calendar=calendar)
maxerr = 0
for n in range(ntimes):
microsecs1 += 1.
date1 = num2date(microsecs1, units, calendar=calendar)
microsecs2 = date2num(date1, units, calendar=calendar)
date2 = num2date(microsecs2, units, calendar=calendar)
err = np.abs(microsecs1 - microsecs2)
maxerr = max(err,maxerr)
assert(err < eps)
assert(date1.strftime(dateformat) == date2.strftime(dateformat))
if verbose:
print('calendar = %s max abs err (microsecs) = %s eps = %s' % \
(calendar,maxerr,eps))
units = 'milliseconds since 1800-01-30 01:01:01'
eps = 0.1
millisecs1 = date2num(dateref,units,calendar=calendar)
maxerr = 0.
for n in range(ntimes):
millisecs1 += 0.001
date1 = num2date(millisecs1, units, calendar=calendar)
millisecs2 = date2num(date1, units, calendar=calendar)
date2 = num2date(millisecs2, units, calendar=calendar)assert(cftime.date2num(cftime.datetime(1, 12, 1, 0, 0, 0, 0, -1, 1), units='days since 01-01-01',calendar='noleap') == 334.0)
assert(cftime.date2num(cftime.num2date(1.0,units='days since 01-01-01',calendar='noleap'),units='days since 01-01-01',calendar='noleap') == 1.0)
assert(cftime.date2num(cftime.DatetimeNoLeap(1980, 1, 1, 0, 0, 0, 0, 6, 1),'days since 1970-01-01','noleap') == 3650.0)
# issue #126
d = cftime.DatetimeProlepticGregorian(1, 1, 1)
assert(cftime.date2num(d, 'days since 0001-01-01',\
'proleptic_gregorian') == 0.0)
# issue #140 (fractional seconds in reference date)
d = datetime.strptime('2018-01-23 09:27:10.950000',"%Y-%m-%d %H:%M:%S.%f")
units = 'seconds since 2018-01-23 09:31:42.94'
assert(cftime.date2num(d, units) == -271.99)
# issue 143 - same answer for arrays vs scalars.
units = 'seconds since 1970-01-01 00:00:00'
times_in = [1261440000.0, 1261440001.0, 1261440002.0, 1261440003.0,
1261440004.0, 1261440005.0]
times_out1 = cftime.num2date(times_in, units)
times_out2 = []
for time_in in times_in:
times_out2.append(cftime.num2date(time_in, units))
dates1 = [str(d) for d in times_out1]
dates2 = [str(d) for d in times_out2]
assert(dates1 == dates2)
# issue #143 formatting of microseconds
d = cftime.num2date(1261440000.015625,units)
# on windows only 100 ms precision
assert(str(d)[0:24] == '2009-12-22 00:00:00.0156')
# issue #152 add isoformat()
assert(d.isoformat()[0:24] == '2009-12-22T00:00:00.0156')
assert(d.isoformat(sep=' ')[0:24] == '2009-12-22 00:00:00.0156')
assert(d.isoformat(sep=' ',timespec='milliseconds') == '2009-12-22 00:00:00.015')
assert(d.isoformat(sep=' ',timespec='seconds') == '2009-12-22 00:00:00')
assert(d.isoformat(sep=' ',timespec='minutes') == '2009-12-22 00:00')# issue #126
d = cftime.DatetimeProlepticGregorian(1, 1, 1)
assert(cftime.date2num(d, 'days since 0001-01-01',\
'proleptic_gregorian') == 0.0)
# issue #140 (fractional seconds in reference date)
d = datetime.strptime('2018-01-23 09:27:10.950000',"%Y-%m-%d %H:%M:%S.%f")
units = 'seconds since 2018-01-23 09:31:42.94'
assert(cftime.date2num(d, units) == -271.99)
# issue 143 - same answer for arrays vs scalars.
units = 'seconds since 1970-01-01 00:00:00'
times_in = [1261440000.0, 1261440001.0, 1261440002.0, 1261440003.0,
1261440004.0, 1261440005.0]
times_out1 = cftime.num2date(times_in, units)
times_out2 = []
for time_in in times_in:
times_out2.append(cftime.num2date(time_in, units))
dates1 = [str(d) for d in times_out1]
dates2 = [str(d) for d in times_out2]
assert(dates1 == dates2)
# issue #143 formatting of microseconds
d = cftime.num2date(1261440000.015625,units)
# on windows only 100 ms precision
assert(str(d)[0:24] == '2009-12-22 00:00:00.0156')
# issue #152 add isoformat()
assert(d.isoformat()[0:24] == '2009-12-22T00:00:00.0156')
assert(d.isoformat(sep=' ')[0:24] == '2009-12-22 00:00:00.0156')
assert(d.isoformat(sep=' ',timespec='milliseconds') == '2009-12-22 00:00:00.015')
assert(d.isoformat(sep=' ',timespec='seconds') == '2009-12-22 00:00:00')
assert(d.isoformat(sep=' ',timespec='minutes') == '2009-12-22 00:00')
assert(d.isoformat(sep=' ',timespec='hours') == '2009-12-22 00')
# issue #165: make sure python datetime returned
d=num2date(0,units="seconds since 2000-01-01 00:00:00",only_use_cftime_datetimes=False)def test_num2date_out_of_range():
numeric_times = 12 * np.array([200000, 400000, 600000])
units = "months since 2000-01-01"
with pytest.raises(OverflowError, match="time values outside range of 64 bit signed integers"):
num2date(numeric_times, units=units, calendar="360_day")maxerr = 0.
for n in range(ntimes):
days1 += 0.00001
date1 = num2date(days1, units, calendar=calendar)
days2 = date2num(date1, units, calendar=calendar)
date2 = num2date(days2, units, calendar=calendar)
err = np.abs(days1 - days2)
maxerr = max(err,maxerr)
assert(err < eps)
assert(date1.strftime(dateformat) == date2.strftime(dateformat))
if verbose:
print('calendar = %s max abs err (days) = %s eps = %s' % \
(calendar,maxerr,eps))
# issue 353
assert (num2date(0, 'hours since 2000-01-01 0') ==
datetime(2000,1,1,0))
# issue 354
num1 = np.array([[0, 1], [2, 3]])
num2 = np.array([[0, 1], [2, 3]])
dates1 = num2date(num1, 'days since 0001-01-01')
dates2 = num2date(num2, 'days since 2001-01-01')
assert( dates1.shape == (2,2) )
assert( dates2.shape == (2,2) )
num1b = date2num(dates1, 'days since 0001-01-01')
num2b = date2num(dates2, 'days since 2001-01-01')
assert( num1b.shape == (2,2) )
assert( num2b.shape == (2,2) )
assert_almost_equal(num1,num1b)
assert_almost_equal(num2,num2b)maxerr = 0
for n in range(ntimes):
microsecs1 += 1.
date1 = num2date(microsecs1, units, calendar=calendar)
microsecs2 = date2num(date1, units, calendar=calendar)
date2 = num2date(microsecs2, units, calendar=calendar)
err = np.abs(microsecs1 - microsecs2)
maxerr = max(err,maxerr)
assert(err < eps)
assert(date1.strftime(dateformat) == date2.strftime(dateformat))
if verbose:
print('calendar = %s max abs err (microsecs) = %s eps = %s' % \
(calendar,maxerr,eps))
units = 'milliseconds since 1800-01-30 01:01:01'
eps = 0.001
millisecs1 = date2num(dateref,units,calendar=calendar)
maxerr = 0.
for n in range(ntimes):
millisecs1 += 0.001
date1 = num2date(millisecs1, units, calendar=calendar)
millisecs2 = date2num(date1, units, calendar=calendar)
date2 = num2date(millisecs2, units, calendar=calendar)
err = np.abs(millisecs1 - millisecs2)
maxerr = max(err,maxerr)
assert(err < eps)
assert(date1.strftime(dateformat) == date2.strftime(dateformat))
if verbose:
print('calendar = %s max abs err (millisecs) = %s eps = %s' % \
(calendar,maxerr,eps))
eps = 1.e-5
units = 'seconds since 0001-01-30 01:01:01'
secs1 = date2num(dateref,units,calendar=calendar)cftime
Time-handling functionality from netcdf4-python
Package Health Score
85 / 100Popular cftime functions
- cftime.__version__
- cftime._cftime._dateparse
- cftime._cftime.date2num
- cftime._cftime.num2date
- cftime._parse_date
- cftime.date2index
- cftime.date2num
- cftime.DateFromJulianDay
- cftime.datetime
- cftime.Datetime360Day
- cftime.DatetimeAllLeap
- cftime.DatetimeGregorian
- cftime.DatetimeJulian
- cftime.DatetimeNoLeap
- cftime.DatetimeProlepticGregorian
- cftime.JulianDayFromDate
- cftime.num2date
- cftime.real_datetime
- cftime.utime