Python基础备忘(一)

Python备忘

dateformat

关于dateformat的使用，有以下例子，最后有官方的directive列表，方便查询；

from datetime import datetime, date, timedelta
date_format = "%Y-%m-%dT%H:%M:%S.%fZ"
start = datetime.strftime(date.today() - timedelta(days=29), date_format)

获取当天日期对象，使用datetime中的date.today();
如果想在当前日期基础上前进或后退时间的话，可以使用datetime的timedelta，例如上例就是获取当天日期的前29天的日期对象；
datetime中的strftime将日期转为str；strptime将str转为时间；
下面是dateformat的directive列表：

Directive	Meaning	Example	Notes
%a	Weekday as locale’s abbreviated name.	Sun, Mon, ..., Sat (en_US); So, Mo, ..., Sa (de_DE)	(1)
%A	Weekday as locale’s full name.	Sunday, Monday, ..., Saturday (en_US); Sonntag, Montag, ..., Samstag (de_DE)	(1)
%w	Weekday as a decimal number, where 0 is Sunday and 6 is Saturday.	0, 1, ..., 6
%d	Day of the month as a zero-padded decimal number.	01, 02, ..., 31
%b	Month as locale’s abbreviated name.	Jan, Feb, ..., Dec (en_US); Jan, Feb, ..., Dez (de_DE)	(1)
%B	Month as locale’s full name.	January, February, ..., December (en_US); Januar, Februar, ..., Dezember (de_DE)	(1)
%m	Month as a zero-padded decimal number.	01, 02, ..., 12
%y	Year without century as a zero-padded decimal number.	00, 01, ..., 99
%Y	Year with century as a decimal number.	1970, 1988, 2001, 2013
%H	Hour (24-hour clock) as a zero-padded decimal number.	00, 01, ..., 23
%I	Hour (12-hour clock) as a zero-padded decimal number.	01, 02, ..., 12
%p	Locale’s equivalent of either AM or PM.	AM, PM (en_US); am, pm (de_DE)	(1), (2)
%M	Minute as a zero-padded decimal number.	00, 01, ..., 59
%S	Second as a zero-padded decimal number.	00, 01, ..., 59	(3)
%f	Microsecond as a decimal number, zero-padded on the left.	000000, 000001, ..., 999999	(4)
%z	UTC offset in the form +HHMM or -HHMM (empty string if the the object is naive).	(empty), +0000, -0400, +1030	(5)
%Z	Time zone name (empty string if the object is naive).	(empty), UTC, EST, CST
%j	Day of the year as a zero-padded decimal number.	001, 002, ..., 366
%U	Week number of the year (Sunday as the first day of the week) as a zero padded decimal number. All days in a new year preceding the first Sunday are considered to be in week 0.	00, 01, ..., 53	(6)
%W	Week number of the year (Monday as the first day of the week) as a decimal number. All days in a new year preceding the first Monday are considered to be in week 0.	00, 01, ..., 53	(6)
%c	Locale’s appropriate date and time representation.	Tue Aug 16 21:30:00 1988 (en_US); Di 16 Aug 21:30:00 1988 (de_DE)	(1)
%x	Locale’s appropriate date representation.	08/16/88 (None); 08/16/1988 (en_US); 16.08.1988 (de_DE)	(1)
%X	Locale’s appropriate time representation.	21:30:00 (en_US); 21:30:00 (de_DE)	(1)
%%	A literal '%' character.	%

发送HTTP请求

使用urllib2，POST例子：

import urllib2
requrl = 'https://something.com/post_something'
headers = {'Content-Type': 'application/json'}
req = urllib2.Request(requrl, datastr, headers)

Get例子：

import urllib2
data = urllib2.urlopen("https://something.com/get_something").read()
print data

使用json

使用json解析json数据：

params = {
        "startTime": 1,
        "endTime": 1,
        "timeIncrement": "day",
        "timeMultiple": 1,
        "descending": False,
        "base": 1,
        "counter": 1
    }
datastr = json.dumps(params)#将json对象转换为str
datajson = json.loads(datastr)#将str转为json