from datetime import datetime, timedelta
import numpy as np
[docs]
def decimal_time_precise(year, month, day, hour=0, minute=0, second=0, start=0):
"""
Convert year-month-day-hour-minute-second to decimal time format, handling various cases including negative seconds
Parameters:
year: Year (can be scalar or array)
month: Month (can be scalar or array)
day: Day (can be scalar or array)
hour, minute, second: Hour, minute, second (can be scalar or array)
start: Starting year (default is 0)
Returns:
Decimal time format (relative to starting year)
"""
# Convert to numpy arrays for uniform processing
year = np.atleast_1d(np.array(year, dtype=float))
month = np.atleast_1d(np.array(month, dtype=float))
day = np.atleast_1d(np.array(day, dtype=float))
hour = np.atleast_1d(np.array(hour, dtype=float))
minute = np.atleast_1d(np.array(minute, dtype=float))
second = np.atleast_1d(np.array(second, dtype=float))
# Check if input is scalar
scalar_input = (len(year) == 1)
# Correct month = 0 cases
month[month == 0] = 1
# Adjust array lengths
n = len(year)
if len(month) < n: month = np.resize(month, n)
if len(day) < n: day = np.resize(day, n)
if len(hour) < n: hour = np.resize(hour, n)
if len(minute) < n: minute = np.resize(minute, n)
if len(second) < n: second = np.resize(second, n)
results = []
for i in range(n):
# Handle negative seconds
# Normalize time to valid hour-minute-second
total_seconds = int(hour[i]) * 3600 + int(minute[i]) * 60 + second[i]
# Handle negative total seconds (subtract a day and adjust)
days_adjust = 0
while total_seconds < 0:
total_seconds += 86400 # Add one day in seconds
days_adjust -= 1 # Decrease one day
# Recalculate hour, minute and second
hr_int = int(total_seconds // 3600) % 24
min_int = int((total_seconds % 3600) // 60)
sec_int = int(total_seconds % 60)
sec_frac = total_seconds - int(total_seconds)
# Calculate datetime
try:
# Ensure date and month are valid
day_val = max(1, int(day[i]))
month_val = max(1, int(month[i]))
# Create base datetime
base_dt = datetime(int(year[i]), month_val, day_val)
# Add day adjustment (handle date decrease due to negative seconds)
if days_adjust != 0:
base_dt += timedelta(days=days_adjust)
# Add time component
dt = datetime(
base_dt.year, base_dt.month, base_dt.day,
hr_int, min_int, sec_int
)
# Add fractional seconds
if sec_frac > 0:
dt += timedelta(seconds=sec_frac)
except ValueError as e:
print(f"Warning: Invalid date calculation for {int(year[i])}-{month_val}-{day_val}, Error: {e}")
# Use the first day of the month as alternative, ensuring time component is valid
try:
dt = datetime(int(year[i]), month_val, 1, hr_int, min_int, sec_int)
print(f"Using first day of month instead: {dt}")
except ValueError:
# If still fails, use the most basic valid date and time
print(f"Fallback to basic valid date")
dt = datetime(int(year[i]), 1, 1, 0, 0, 0)
# Calculate the first day of the year
year_start = datetime(int(year[i]), 1, 1)
# Calculate days in the year (handle leap year)
if int(year[i]) % 4 == 0 and (int(year[i]) % 100 != 0 or int(year[i]) % 400 == 0):
days_in_year = 366
else:
days_in_year = 365
# Calculate days passed from year start to now (including hour-minute-second)
days_passed = (dt - year_start).total_seconds() / 86400
# Calculate decimal time
decimal_time = (year[i] - start) + days_passed / days_in_year
results.append(decimal_time)
# Return result (scalar or array)
if scalar_input:
return results[0]
return np.array(results)
[docs]
def ymd_time_precise(time, start):
"""
Convert decimal time to year-month-day format, using datetime library
Parameters:
time: Decimal time (can be scalar or array)
start: Starting year
Returns:
Array containing year, month, day (each row corresponds to one time point)
"""
# Convert to numpy array for uniform processing
time = np.atleast_1d(np.array(time, dtype=float))
# Check if input is scalar
scalar_input = (len(time) == 1)
# Create result array containing year, month, day
result = np.zeros((len(time), 3))
for i in range(len(time)):
try:
# Calculate full year
full_year = int(time[i]) + int(start)
# Calculate fractional part of year
year_fraction = time[i] - int(time[i])
# Determine days in the year (handle leap year)
if full_year % 4 == 0 and (full_year % 100 != 0 or full_year % 400 == 0):
days_in_year = 366
else:
days_in_year = 365
# Calculate days passed (including fractional part)
days_passed = year_fraction * days_in_year
# Separate integer days and fractional part
days_int = int(days_passed)
days_frac = days_passed - days_int
# Calculate corresponding date
target_date = datetime(full_year, 1, 1) + timedelta(days=days_int)
# Store year-month-day result
result[i, 0] = full_year
result[i, 1] = target_date.month
result[i, 2] = target_date.day
except Exception as e:
print(f"Warning: Error converting time {time[i]} + {start}: {e}")
# Use default value (January 1st of current year)
result[i, 0] = int(start)
result[i, 1] = 1
result[i, 2] = 1
# Return result (scalar or array)
if scalar_input:
return result[0]
return result
