datetime_Object_learning.ipynb

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   "source": [
    "#https://docs.python.org/2/library/datetime.html#datetime-objects\n",
    "import datetime\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "#class datetime.datetime(year, month, day[, hour[, minute[, second[, microsecond[, tzinfo]]]]])¶\n",
    "#The year, month and day arguments are required. tzinfo may be None, or an instance of a tzinfo subclass. The remaining arguments may be ints or longs, in the following ranges:\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "datetime.datetime(2018, 5, 13, 12, 13, 58, 232919)"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#1) 返回当前的时间\n",
    "#Return the current local datetime, with tzinfo None. This is equivalent to datetime.fromtimestamp(time.time()). See also now(), fromtimestamp().\n",
    "datetime.datetime.today()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "datetime.datetime(2018, 5, 13, 4, 16, 40, 91624)"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "datetime.datetime.utcnow()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "#2) classmethod datetime.strptime(date_string, format)\n",
    "#Return a datetime corresponding to date_string, parsed according to format. This is equivalent to datetime(*(time.strptime(date_string, format)[0:6])). ValueError is raised if the date_string and format can’t be parsed by time.strptime() or if it returns a value which isn’t a time tuple. For a complete list of formatting directives, see section strftime() and strptime() Behavior.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "datetime.datetime(2005, 7, 14, 12, 30)"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#3) examples\n",
    "from datetime import datetime, date, time\n",
    "#Using datetime.combine()\n",
    "d = date(2005, 7, 14)\n",
    "t = time(12, 30)\n",
    "datetime.combine(d, t)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "datetime.datetime(2018, 5, 13, 12, 23, 39, 524568)"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Using datetime.now() or datetime.utcnow()\n",
    "datetime.now() #因为导入的形式不一样，上面是只有 import datetime， 下面是from datetime import datatime, date, time"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "datetime.datetime(2006, 11, 21, 16, 30)"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Using datetime.strptime()\n",
    "dt = datetime.strptime(\"21/11/06 16:30\", \"%d/%m/%y %H:%M\")\n",
    "dt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2006\n",
      "11\n",
      "21\n",
      "16\n",
      "30\n",
      "0\n",
      "1\n",
      "325\n",
      "-1\n"
     ]
    }
   ],
   "source": [
    "#Using datetime.timetuple() to get tuple of all attributes\n",
    "tt  = dt.timetuple()\n",
    "for it in tt:\n",
    "    print(it)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Tuesday, 21, November, 2006, 16:30:00: 30PM'"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#Formatting datetime\n",
    "dt.strftime(\"%A, %d, %B, %Y, %T: %M%p\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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