将2个列表根据元素位置合并成字典:
方法一:
>>> a ['shanghai', 'chengdu', 'shandong'] >>> b ['wo', 'chun', 'bing'] >>> c = dict(zip(a,b)) >>> c {'shanghai': 'wo', 'chengdu': 'chun', 'shandong': 'bing'} >>> c['shandong'] 'bing'
取2个列表同样位置的元素:
>>> a ['shanghai', 'chengdu', 'shandong'] >>> b ['wo', 'chun', 'bing'] >>> b[a.index('shandong')] 'bing' >>>
创建列表
#方法一 >>> dict1 = dict((('a' ,20), ('b' ,30))) >>> dict1 {'a': 20, 'b': 30} #方法二: >>> dict2 = dict('i'='shandong', 'she'='chengdu') SyntaxError: keyword can't be an expression >>> dict2 = dict(i='shandong', she='chengdu') >>> dict2 {'i': 'shandong', 'she': 'chengdu'} #列表增加元素 >>> dict2['he'] = 'chongqing' >>> dict2 {'i': 'shandong', 'she': 'chengdu', 'he': 'chongqing'}
#创建字典,指定values为kong
>>> c = dict.fromkeys(('1', '2'), 'kong') >>> c {'1': 'kong', '2': 'kong'} >>> c.values() dict_values(['kong', 'kong']) >>> c.items() dict_items([('1', 'kong'), ('2', 'kong')]) >>> c.keys() dict_keys(['1', '2']) #c字典增加key和value >>> c['3']='duo' >>> c {'1': 'kong', '2': 'kong', '3': 'duo'} >>>
>>> d = dict.fromkeys((range(5)), 'a') >>> d {0: 'a', 1: 'a', 2: 'a', 3: 'a', 4: 'a'} >>> for key in d.keys(): print(key) 0 1 2 3 4 >>> for value in d.values(): print(value) a a a a a >>> for k, v in d.items(): print(k, v) 0 a 1 a 2 a 3 a 4 a
>>> for k in d.items(): print(k) (0, 'a') (1, 'a') (2, 'a') (3, 'a') (4, 'a')
>>> d {0: 'a', 1: 'a', 2: 'a', 3: 'a', 4: 'a'} # get取值时如果取的值不存在则返回none,不报错 >>> d.get('5') >>> print(d.get(5)) None >>> 4 in d True >>> 5in d False >>> d.clear() >>> d {} >>> a = {'1':'one', '2':'two', '3':'three'} # 浅拷贝 >>> b = a.copy() >>> c = a >>> a {'1': 'one', '2': 'two', '3': 'three'} >>> b {'1': 'one', '2': 'two', '3': 'three'} >>> c {'1': 'one', '2': 'two', '3': 'three'} >>> c['4']='four' >>> a {'1': 'one', '2': 'two', '3': 'three', '4': 'four'} >>> b {'1': 'one', '2': 'two', '3': 'three'} >>> c {'1': 'one', '2': 'two', '3': 'three', '4': 'four'} >>> e ={'xiaobai':'dog'} # 将字典e的元素update到b字典中 >>> b.update(e) >>> b {'1': 'one', '2': 'two', '3': 'three', 'xiaobai': 'dog'}
>>> b {'1': 'one', '2': 'two', '3': 'three', 'xiaobai': 'dog'} >>> cc =10 >>> dd = 'key' # update格式为括号内加字典,即d.update({key:value}) >>> b.update({cc:dd}) >>> b {'1': 'one', '2': 'two', '3': 'three', 'xiaobai': 'dog', 10: 'key'}