1、如果想得到一个列表的index和内容，可以通过enumerate快速实现
drinks = [‘coffee’,’tea’, ‘milk’, ‘water’]for index, drink in enumerate(drinks): print (‘item {} is {}’.format(index, drink))#result# item 0 is coffee# item 1 is tea# item 2 is milk# item 3 is water
2、python 中的set， 是一个无序不重复元素集，可以非常方便的进行关系测试和消除重复元素
# deduplicate a list fastprint (set([‘ham’, ‘eggs’,’bacon’,’ham’]))# result# {‘ham’, ‘eggs’, ‘bacon’}# compare list to find difference/similarities # {} without “key”:”value” pairs makes a setmenu = {‘pancakes’, ‘ham’, ‘eggs’, ‘bacon’}new_menu = {‘coffee’, ‘ham’, ‘eggs’, ‘bagels’, ‘bacon’}new_items = new_menu.difference(menu)print (‘try our new’, ‘, ‘.join(new_items))# result: try our new coffee, bagelsdiscontinued_items = menu.difference(new_menu)print (‘sorry, we no longer have’, ‘, ‘.join(discontinued_items))# result: sorry, we no longer have panckesold_items = new_menu.intersection(menu)print (‘or get the same old’, ‘, ‘.join(old_items))# result: or ger the same old eggs, ham, baconfull_menu = new_menu.union(menu)print (‘at one time or another, we have served ‘, ‘,’.join(full_menu))
3、namedtuple 生成可以使用名字来访问元素内容的tuple 子类，非常方便
import collectionshttp:lightobject = collections.namedtuple(‘lightobject’, [‘shortname’, ‘otherprop’])n = lightobject(shortname = ‘something’, otherprop = ‘something else’)n.shortname # something
4、deque 双段队列，最大好处就是可以从头部添加和删除对象 popleft()、 appendleft()
import collectionsd = collections.deque(‘123456’)print d.popleft() # ‘1’d.appendleft(‘7’)print d # deque([‘7′,’2′,’3′,’4′,’5′,’6’])
5、counter 同样是collections 中的，主要用来计数
import collectionsc = collections.counter(‘abcab’)print c #couner({‘a’:2,’b’:2,’c’:1}
elements 方法返回一个迭代器，将生成counter 知道的所有元素；most_common（n）生成一个序列，包含最常用的输入值及相应计数
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