儒略日和常规日期的转换（Python版）

天文地理学科经常会使用儒略日（Julian Day）
这里使用Python的datetime模块实现其和常规日期的转换

from datetime import datetimedef d_to_jd(time):    fmt = '%Y.%m.%d'    dt = datetime.strptime(time, fmt)    tt = dt.timetuple()    return tt.tm_year * 1000 + tt.tm_ydaydef jd_to_time(time):    dt = datetime.strptime(time, '%Y%j').date()    fmt = '%Y.%m.%d'    return dt.strftime(fmt)if '__main__' == __name__:    flag = input('Please input the date transform type: 1 for Julian day to date; 2 for date to Julian day:')    if 1 == int(flag):        time = input('Please input the date (YY.MM.DD):')        print(d_to_jd(time))    elif 2 == int(flag):        time = input('Please input the Julian day:')        print(jd_to_time(time))

运行结果：

Please input the date transform type: 1 for Julian day to date; 2 for date to Julian day:1Please input the date (YY.MM.DD):2016.08.212016234

Please input the date transform type: 1 for Julian day to date; 2 for date to Julian day:2Please input the Julian day:20162342016.08.21