python hidden features
from http://stackoverflow.com/questions/101268/hidden-features-of-python
http://www.okpython.com/bbs/thread-3434-1-1.html
http://www.okpython.com/bbs/thread-3436-1-2.html
http://www.okpython.com/bbs/thread-3437-1-2.html
http://www.okpython.com/bbs/thread-3438-1-1.html
http://www.okpython.com/bbs/thread-3439-1-1.html
http://www.okpython.com/bbs/thread-3440-1-1.html
http://www.okpython.com/bbs/thread-3441-1-1.html
#74 太懒而不愿对字典进行初始化？没问题！
# n Python > 2.3:
from collections import defaultdict
In Python <= 2.3:
def defaultdict(type_):
class Dict(dict):
def __getitem__(self, key):
return self.setdefault(key, type_())
return Dict()
In any version:
d = defaultdict(list)
for stuff in lots_of_stuff:
d[stuff.name].append(stuff)
相关文档：
>>> a="abcd"
>>> ",".join(a)
'a,b,c,d'
>>> "|".join(['a','b','c'])
'a|b|c'
>>> ",".join(('a','b','c'))
'a,b,c'
>>> ",".join({'a':1,'b':2,'c':3})
'a,c,b' ......
eval(str [,globals [,locals ]])函数将字符串str当成有效Python表达式来求值，并返回计算结果。
同样地, exec语句将字符串str当成有效Python代码来执行.提供给exec的代码的名称空间和exec语句的名称空间相同.
最后，execfile(filename [,globals [,locals ]])函数可以用来执行一个文件,看下面的例子:
>>> ev ......
找了半天没找着，终于在英文站点上找到，还有感谢群里的石头和球迷
>>> s = datetime.datetime(2009,1,1)
>>> time.mktime(s.timetuple())
1230739200.0
别外付一个python对时间的一些函数，很好用的
我们先导入必须用到的一个module
>>> import time
设置一个时间的格式，下面会用到
& ......
