>>> os.environ["HOME"]'C:\\Users\\Administrator'>>> os.getcwd() #获得当前的目录'D:\\new'>>> os.getenv("QTDIR") #获取环境变量的值'D:\\vs-qt-src-4.7.4\\qt-src-4.7.4'os.putenv(varname, value) #设置环境变量的值os.mkdir(path[, mode])>>> os.mkdir("aa")>>> os.rmdir("aa")>>>os.makedirs("aa\\bb\\cc") 多级目录os.removedirs(path)¶os.remove("d:\\new\\hello.txt") #删除文件，如果是目录的话，出错os.rename("test.txt","a.txt") random.randint(a, b)Return a random integer N such that a <= N <= b.random.choice(seq)Return a random element from the non-empty sequence seq. If seq is empty, raises IndexError.random.random()Return the next random floating point number in the range [0.0, 1.0).random.shuffle(x[, random]) 随机排序序列random.uniform(a, b)¶返回a<=N<=b之间的浮点数random.randrange([start], stop[, step])想当于choice(range(start, stop, step))>>> random.random() # Random float x, 0.0 <= x < 1.00.37444887175646646>>> random.uniform(1, 10) # Random float x, 1.0 <= x < 10.01.1800146073117523>>> random.randint(1, 10) # Integer from 1 to 10, endpoints included7>>> random.randrange(0, 101, 2) # Even integer from 0 to 10026>>> random.choice('abcdefghij') # Choose a random element'c'>>> items = [1, 2, 3, 4, 5, 6, 7]>>> random.shuffle(items)>>> items[7, 3, 2, 5, 6, 4, 1]>>> random.sample([1, 2, 3, 4, 5], 3) # Choose 3 elements[4, 1, 5]>>> datetime.MAXYEAR9999>>> datetime.MINYEAR1>>> a=datetime.date(,2,1)>>> a.today()datetime.date(, 11, 26)>>> a.year>>> a.month2>>> a.day1>>> import time>>> from datetime import date>>> today = date.today()>>> todaydatetime.date(, 12, 5)>>> my_birthday = date(today.year, 6, 24)>>> if my_birthday < today:...my_birthday = my_birthday.replace(year=today.year + 1)>>> my_birthdaydatetime.date(, 6, 24)>>> time_to_birthday = abs(my_birthday - today) #计算日期之差>>> time_to_birthday.days202>>> datetime.now() #当前时间datetime.datetime(, 11, 26, 10, 40, 10, 283000)>>> datetime.utcnow()datetime.datetime(, 11, 26, 2, 40, 34, 809000)>>> a=date(,7,14) #日期和时间进行合并>>> t=time(12,30,12)>>> bine(a,t)datetime.datetime(, 7, 14, 12, 30, 12)>>> dt = datetime.strptime("21/11/06 16:30", "%d/%m/%y %H:%M")>>> dtdatetime.datetime(, 11, 21, 16, 30)>>> from datetime import timedelta, datetime, tzinfo>>> class GMT1(tzinfo):...def __init__(self): # DST starts last Sunday in March... d = datetime(dt.year, 4, 1) # ends last Sunday in October... self.dston = d - timedelta(days=d.weekday() + 1)... d = datetime(dt.year, 11, 1)... self.dstoff = d - timedelta(days=d.weekday() + 1)...def utcoffset(self, dt):... return timedelta(hours=1) + self.dst(dt)...def dst(self, dt):... if self.dston <= dt.replace(tzinfo=None) < self.dstoff:... return timedelta(hours=1)... else:... return timedelta(0)...def tzname(self,dt):...return "GMT +1"...>>> class GMT2(tzinfo):...def __init__(self):... d = datetime(dt.year, 4, 1)... self.dston = d - timedelta(days=d.weekday() + 1)... d = datetime(dt.year, 11, 1)... self.dstoff = d - timedelta(days=d.weekday() + 1)...def utcoffset(self, dt):... return timedelta(hours=1) + self.dst(dt)...def dst(self, dt):... if self.dston <= dt.replace(tzinfo=None) < self.dstoff:... return timedelta(hours=2)... else:... return timedelta(0)...def tzname(self,dt):... return "GMT +2"...>>> gmt1 = GMT1()>>> # Daylight Saving Time>>> dt1 = datetime(, 11, 21, 16, 30, tzinfo=gmt1)>>> dt1.dst()datetime.timedelta(0)>>> dt1.utcoffset()datetime.timedelta(0, 3600)>>> dt2 = datetime(, 6, 14, 13, 0, tzinfo=gmt1)>>> dt2.dst()datetime.timedelta(0, 3600)>>> dt2.utcoffset()datetime.timedelta(0, 7200)>>> # Convert datetime to another time zone>>> dt3 = dt2.astimezone(GMT2())>>> dt3# doctest: +ELLIPSISdatetime.datetime(, 6, 14, 14, 0, tzinfo=<GMT2 object at 0x...>)>>> dt2# doctest: +ELLIPSISdatetime.datetime(, 6, 14, 13, 0, tzinfo=<GMT1 object at 0x...>)>>> dt2.utctimetuple() == dt3.utctimetuple()Trueclass datetime.time(hour[, minute[, second[, microsecond[, tzinfo]]]])>>> a=time(10,46,12)>>> a.mindatetime.time(0, 0)>>> a.maxdatetime.time(23, 59, 59, 999999)>>> a.hour10>>> a.minute46>>> a.second12>>> a.microsecond0class collections.Counter([iterable-or-mapping])A Counter is a dict subclass for counting hashable objects.>>> # Tally occurrences of words in a list>>> cnt = Counter()>>> for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']:...cnt[word] += 1>>> cntCounter({'blue': 3, 'red': 2, 'green': 1})>>> # Find the ten most common words in Hamlet>>> import re>>> words = re.findall('\w+', open('hamlet.txt').read().lower())>>> Counter(words).most_common(10)[('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631),('you', 554), ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)]>>> c = Counter(['eggs', 'ham'])>>> c['bacon']# count of a missing element is zero0>>> c['sausage'] = 0 # counter entry with a zero count>>> del c['sausage'] # del actually removes the entry>>> c = Counter(a=4, b=2, c=0, d=-2)>>> list(c.elements())['a', 'a', 'a', 'a', 'b', 'b']most_common([n]) #出现次数最多的n个>>> Counter('abracadabra').most_common(3)[('a', 5), ('r', 2), ('b', 2)]>>> c = Counter(a=4, b=2, c=0, d=-2)>>> d = Counter(a=1, b=2, c=3, d=4)>>> c.subtract(d)Counter({'a': 3, 'b': 0, 'c': -3, 'd': -6})>>> c = Counter(a=4, b=2, c=0, d=-2)>>> sum(c.values()) # total of all counts4>>> list(c)['a', 'c', 'b', 'd']>>> set(c)set(['a', 'c', 'b', 'd'])>>> dict(c){'a': 4, 'c': 0, 'b': 2, 'd': -2}>>> c.items()[('a', 4), ('c', 0), ('b', 2), ('d', -2)]>>> c.most_common()[:-2:-1] # c.most_common()[:-n:-1] n least #common elements[('d', -2)]>>> c+=Counter()>>> cCounter({'a': 4, 'b': 2})>>> c.clear()>>> cCounter()>>> c = Counter(a=3, b=1)>>> d = Counter(a=1, b=2)>>> c + d # add two counters together: c[x] + d[x]Counter({'a': 4, 'b': 3})>>> c - d # subtract (keeping only positive counts)Counter({'a': 2})>>> c & d # intersection: min(c[x], d[x])Counter({'a': 1, 'b': 1})>>> c | d # union: max(c[x], d[x])Counter({'a': 3, 'b': 2})>>> from collections import deque>>> d = deque('ghi') # make a new deque with three items>>> for elem in d: # iterate over the deque's elements...print elem.upper()GHI>>> d.append('j')# add a new entry to the right side>>> d.appendleft('f')# add a new entry to the left side>>> d # show the representation of the dequedeque(['f', 'g', 'h', 'i', 'j'])>>> d.pop()# return and remove the rightmost item'j'>>> d.popleft() # return and remove the leftmost item'f'>>> list(d)# list the contents of the deque['g', 'h', 'i']>>> d[0] # peek at leftmost item'g'>>> d[-1] # peek at rightmost item'i'>>> list(reversed(d))# list the contents of a deque in reverse['i', 'h', 'g']>>> 'h' in d# search the dequeTrue>>> d.extend('jkl') # add multiple elements at once>>> ddeque(['g', 'h', 'i', 'j', 'k', 'l'])>>> d.rotate(1) # right rotation>>> ddeque(['l', 'g', 'h', 'i', 'j', 'k'])>>> d.rotate(-1) # left rotation>>> ddeque(['g', 'h', 'i', 'j', 'k', 'l'])>>> deque(reversed(d))# make a new deque in reverse orderdeque(['l', 'k', 'j', 'i', 'h', 'g'])>>> d.clear() # empty the deque>>> d.pop()# cannot pop from an empty dequeTraceback (most recent call last):File "<pyshell#6>", line 1, in -toplevel-d.pop()IndexError: pop from an empty deque>>> d.extendleft('abc') # extendleft() reverses the input order>>> ddeque(['c', 'b', 'a'])def tail(filename, n=10):'Return the last n lines of a file'return deque(open(filename), n)def moving_average(iterable, n=3):# moving_average([40, 30, 50, 46, 39, 44]) --> 40.0 42.0 45.0 43.0# /wiki/Moving_averageit = iter(iterable)d = deque(itertools.islice(it, n-1))d.appendleft(0)s = sum(d)for elem in it:s += elem - d.popleft()d.append(elem)yield s / float(n)def delete_nth(d, n):d.rotate(-n)d.popleft()d.rotate(n)class collections.defaultdict([default_factory[, ...]])>>> s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]>>> d = defaultdict(list)>>> for k, v in s:...d[k].append(v)...>>> d.items()[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]>>> d = {}>>> for k, v in s:...d.setdefault(k, []).append(v)...>>> d.items()[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]>>> s = 'mississippi'>>> d = defaultdict(int)>>> for k in s:...d[k] += 1...>>> d.items()[('i', 4), ('p', 2), ('s', 4), ('m', 1)]>>> s = [('red', 1), ('blue', 2), ('red', 3), ('blue', 4), ('red', 1), ('blue', 4)]>>> d = defaultdict(set)>>> for k, v in s:...d[k].add(v)...>>> d.items()[('blue', set([2, 4])), ('red', set([1, 3]))]>>> def heapsort(iterable):...'Equivalent to sorted(iterable)'...h = []...for value in iterable:... heappush(h, value)...return [heappop(h) for i in range(len(h))]...>>> heapsort([1, 3, 5, 7, 9, 2, 4, 6, 8, 0])[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]>>> h = []>>> heappush(h, (5, 'write code'))>>> heappush(h, (7, 'release product'))>>> heappush(h, (1, 'write spec'))>>> heappush(h, (3, 'create tests'))>>> heappop(h)(1, 'write spec')#coding=utf-8#堆的实例from heapq import heappush, heappop, heappushpop, heapify, heapreplace, nlargest,\nsmallestheap=[]heappush(heap,"A");heappush(heap,"C");heappush(heap,"B");print heapheappop(heap) #弹出堆中最小的元素print heapvar=heappushpop(heap,"D") #返回并弹出堆中最小的元素，并且将D压入堆print varprint heapvar=heapreplace(heap,"E") #返回并弹出堆中最小的元素，并且将D压入堆,print varprint heaplist=[1,2,3,4,5,6,7,8,9,0]heapify(list);print listprint nlargest(3,list) #返回堆中最大的3个print nsmallest(3,list) #返回堆中最小的3个
