3-21理解

一、

二、理解RegExp中的[]

　　[xyz] 字符集合。匹配所包含的任意一个字符。例如，“[abc]”可以匹配“plain”中的“a”。　　

　　[abc] 等价于(a|b|c)

 

三、python包查看帮助  help(time)  然后会有相应的方法和功能解释

time.time()
radom.randint(1,100)  产生1-100之间的随机数，包含1和100

In [4]: help(time)
Help on built-in module time:

NAME
time - This module provides various functions to manipulate time values.

FILE
(built-in)

DESCRIPTION
There are two standard representations of time. One is the number
of seconds since the Epoch, in UTC (a.k.a. GMT). It may be an integer
or a floating point number (to represent fractions of seconds).
The Epoch is system-defined; on Unix, it is generally January 1st, 1970.
The actual value can be retrieved by calling gmtime(0).

The other representation is a tuple of 9 integers giving local time.
The tuple items are:
year (four digits, e.g. 1998)
month (1-12)
day (1-31)
hours (0-23)
minutes (0-59)
seconds (0-59)
weekday (0-6, Monday is 0)
Julian day (day in the year, 1-366)
DST (Daylight Savings Time) flag (-1, 0 or 1)
If the DST flag is 0, the time is given in the regular time zone;
if it is 1, the time is given in the DST time zone;
if it is -1, mktime() should guess based on the date and time.

Variables:

timezone -- difference in seconds between UTC and local standard time
altzone -- difference in seconds between UTC and local DST time
daylight -- whether local time should reflect DST
tzname -- tuple of (standard time zone name, DST time zone name)

Functions:

time() -- return current time in seconds since the Epoch as a float
clock() -- return CPU time since process start as a float
sleep() -- delay for a number of seconds given as a float
gmtime() -- convert seconds since Epoch to UTC tuple
localtime() -- convert seconds since Epoch to local time tuple
asctime() -- convert time tuple to string
ctime() -- convert time in seconds to string
-- More --