# 字典的value可以是任何值 test = {'k1':'v1', 'k2':True, 'k3':[1,2,3,4,{'t1':'v2','t2':'v3'},5,6], 'k4':(88,99,66) } print(test) {'k1': 'v1', 'k2': True, 'k3': [1, 2, 3, 4, {'t1': 'v2', 't2': 'v3'}, 5, 6], 'k4': (88, 99, 66)}
# 布尔值(True=1,False=0)可以作为key但不能有重复。 列表,字典是不能作为字典的key test = { 1:'abd', 'k1':'esd', True: '136', (11,22):123, [1,b,8]:'bes', 【列表,字典是不能作为字典的key】
}
test = { 1:'abd', 'k1':'esd', True: '136', } print(test) {1: '136', 'k1': 'esd'} test1 = { '2':'abd', 'k1':'esd', True: '136', } print(test1) {'2': 'abd', 'k1': 'esd', True: '136'}
# 字典是无序的
# 通过索引的方式找到指定元素。 test = {'k1':'v1', 'k2':True, 'k3':[1,2,3,4,{'t1':'v2','t2':(12,18)},5,6], 'k4':(88,99,66) } v = test['k3'][4]['t2'][0] print(v) 12
# 字典支持del删除。 test = {'k1':'v1', 'k2':True, 'k3':[1,2,3,4,{'t1':'v2','t2':(12,18)},5,6], 'k4':(88,99,66) } del test['k3'][4]['t2'] del test['k4'] print(test) {'k1': 'v1', 'k2': True, 'k3': [1, 2, 3, 4, {'t1': 'v2'}, 5, 6]}
# for循环默认循环的是key test = {'k1':'v1', 'k2':True, 'k3':[1,2,3,4,{'t1':'v2','t2':(12,18)},5,6], 'k4':(88,99,66) } for item in test: print(item) k1 k2 k3 k4
# for循环加 .value() 循环键的值 test = {'k1':'v1', 'k2':True, 'k3':[1,2,3,4,{'t1':'v2','t2':(12,18)},5,6], 'k4':(88,99,66) } for item in test.values(): print(item) v1 True [1, 2, 3, 4, {'t1': 'v2', 't2': (12, 18)}, 5, 6] (88, 99, 66)
## for循环 for k,v in 字典变量.items(): 循环所有 test = {'k1':'v1', 'k2':True, 'k3':[1,2,3,4,{'t1':'v2','t2':(12,18)},5,6], 'k4':(88,99,66) } for k,v in test.items(): print(k,v) k1 v1 k2 True k3 [1, 2, 3, 4, {'t1': 'v2', 't2': (12, 18)}, 5, 6] k4 (88, 99, 66)
# dict.fromkeys([],)根据序列,创建字典,并指定统一的值 v = dict.fromkeys(['k1','k2','k3'],888) print(v) {'k1': 888, 'k2': 888, 'k3': 888}
# dic.get() 根据key获取值,key不存在时,可以指定默认值(none) dic ={'k1':'v1'} v = dic.get('k1') print(v) v1 dic ={'k1':'v1'} v = dic.get('k8') print(v) None
pop(),popitem() 删除并取值 dic ={'k1':'v1', 'k2':'v2', 'k3':'v3' } v = dic.pop('k1') print(v) print(dic) v1 {'k2': 'v2', 'k3': 'v3'} dic ={'k1':'v1', 'k2':'v2', 'k3':'v3' } v = dic.popitem() print(v) print(dic) ('k3', 'v3') {'k1': 'v1', 'k2': 'v2'}
### setdefault() 设置值 # 已存在,不设置,获取当前key对应的值 dic ={'k1':'v1', 'k2':'v2', 'k3':'v3' } v = dic.setdefault('k1','888') print(v) print(dic) v1 {'k1': 'v1', 'k2': 'v2', 'k3': 'v3'}
# 不存在,设置,获取当前key对应的值 dic ={'k1':'v1', 'k2':'v2', 'k3':'v3' } v = dic.setdefault('k6','888') print(v) print(dic) 888 {'k1': 'v1', 'k2': 'v2', 'k3': 'v3', 'k6': '888'}
# update() 字典更新 两种方法注意括号的使用 dic ={'k1':'v1', 'k2':'v2', 'k3':'v3' } v = dic.update({'k1':'888'}) 第一种 print(dic) v1 = dic.update(k3=666) 第二种 print(dic) {'k1': '888', 'k2': 'v2', 'k3': 'v3'} {'k1': '888', 'k2': 'v2', 'k3': 666}