1、Dictionary语法
>>> phonebook = {'Alice': '2341', 'Beth': '9102', 'Cecil': '3258'}
>>> phonebook = {'Alice': '2341', 'Alice': '9102', 'Cecil': '3258'}>>> phonebook{'Alice': '9102', 'Cecil': '3258'}
>>> items = [('name', 'Gumby'), ('age', 42)]>>> d = dict(items)>>> d{'age': 42, 'name': 'Gumby'}
>>> d = dict(name='Gumby', age=42)>>> d{'age': 42, 'name': 'Gumby'} 2、基本Dictionary操作
>>> x = {}>>> x[42] = 'Foobar'>>> x{42: 'Foobar'}
3、使用Dictionary格式化String
>>> template = '''<html><head><title>%(title)s</title></head><body><h1>%(title)s</h1><p>%(text)s</p></body>'''>>> data = {'title': 'My Home Page', 'text': 'Welcome to my home page!'}>>> print template % data<html><head><title>My Home Page</title></head><body><h1>My Home Page</h1><p>Welcome to my home page!</p></body> 4、Dictionary方法
(1) clear:移去Dictionary中所有的元素
>>> d = {'age': 42, 'name': 'Gumby'}>>> d{'age': 42, 'name': 'Gumby'}>>> d.clear()>>> d{}
(2) copy:返回具有相同key/value对的新Dictionary(注意value值是共用的)
>>> x = {'username': 'admin', 'machines': ['foo', 'bar', 'baz']}>>> y = x.copy()>>> y['username'] = 'mlh'>>> y['machines'].remove('bar')>>> y{'username': 'mlh', 'machines': ['foo', 'baz']}>>> x{'username': 'admin', 'machines': ['foo', 'baz']}
>>> from copy import deepcopy>>> d = {}>>> d['names'] = ['Alfred', 'Bertrand']>>> c = d.copy()>>> dc = deepcopy(d)>>> d['names'].append('Clive')>>> c{'names': ['Alfred', 'Bertrand', 'Clive']}>>> dc{'names': ['Alfred', 'Bertrand']}
(3) fromkeys:根据给定的key值创建新的Dictionary,缺省value值为None
>>> {}.fromkeys(['name', 'age']){'age': None, 'name': None}
>>> dict.fromkeys(['name', 'age']){'age': None, 'name': None}
>>> dict.fromkeys(['name', 'age'], '(unknown)'){'age': '(unknown)', 'name': '(unknown)'}
(4) get:获取项目的value值(不常用)
>>> d = {}>>> print d['name']Traceback (most recent call last): File "<interactive input>", line 1, in ?KeyError: 'name'>>> print d.get('name')None
>>> d.get('name', 'N/A')'N/A'
(5) has_key:检查Dictionary中是否有指定key
>>> d = {}>>> d.has_key('name')0>>> d['name'] = 'Eric'>>> d.has_key('name')1
(6) items和iteritems
>>> d = {'title': 'Python Web Site', 'url': 'http://www.python.org', 'spam': 0}>>> d.items()[('url', 'http://www.python.org'), ('spam', 0), ('title', 'Python Web Site')]
>>> d.iteritems()<dictionary-itemiterator object at 0x0101CA60>>>> list(d.iteritems())[('url', 'http://www.python.org'), ('spam', 0), ('title', 'Python Web Site')]
(7) keys和iterkeys
>>> d.keys()['url', 'spam', 'title']>>> d.iterkeys()<dictionary-keyiterator object at 0x01073720>>>> list(d.iterkeys())['url', 'spam', 'title']
(8) pop:根据指定key返回value,并从Dictionary中移去该项目:
>>> d = {'x': 1, 'y': 2}>>> d.pop('x')1>>> d{'y': 2}
(9) popitem:从Dictionary中随机弹出一个项目返回(Dictionary中的项目是无序的)
>>> d = {'title': 'Python Web Site', 'url': 'http://www.python.org', 'spam': 0}>>> d.popitem()('url', 'http://www.python.org')>>> d{'spam': 0, 'title': 'Python Web Site'}
(10) setdefault:根据指定的key值,对不在Dictionary的项目设置value值
>>> d = {}>>> d.setdefault('name', 'N/A')'N/A'>>> d{'name': 'N/A'}>>> d['name'] = 'Gumby'>>> d.setdefault('name', 'N/A')'Gumby'>>> d{'name': 'Gumby'}
(11) update:使用另一个Dictionary的项目来更新指定Dictionary
>>> d = {'title': 'Python Web Site', 'url': 'http://www.python.org', 'changed': 'Mar 14 22:09:15 MET 2005'}>>> x = {'title': 'Python Language Website'}>>> d.update(x)>>> d{'url': 'http://www.python.org', 'changed': 'Mar 14 22:09:15 MET 2005', 'title': 'Python Language Website'}(12) values和itervalues>>> d.values()['http://www.python.org', 'Mar 14 22:09:15 MET 2005', 'Python Language Website']>>> d.itervalues()<dictionary-valueiterator object at 0x01073900>>>> list(d.itervalues())