字典
1.
#dict
'''
#数据类型划分:可变数据类型,不可变数据类型
不可变数据类型:元组,bool int str 可哈希
可变数据类型:list,dict set 不可哈希
dict key 必须是不可变数据类型,可哈希,
value:任意数据类型。
dict 优点:二分查找去查询
存储大量的关系型数据
特点:无序的
2.
dic1 = {'age': 18, 'name': 'jin', 'sex': 'male',}
#增
# dic1['high'] = 185 #没有键值对,添加 # dic1['age'] = 16 #如果有键,则值覆盖 # dic1.setdefault('weight') # 有键值对,不做任何改变,没有才添加。 # dic1.setdefault('weight',150) #dic1.setdefault('name','dage') #print(dic1)
#删
print(dic1.pop('age',)) # 有返回值,按键去删除 print(dic1.pop('二哥','meiyou')) # 可设置返回值 print(dic1) ''' # print(dic1.popitem()) # 随机删除 有返回值 元组里面是删除的键值。 # # print(dic1) # del dic1['name'] # print(dic1) # del dic1 # print(dic1) # dic1.clear() #清空字典
#改
#改 update # dic1['age'] = 16 ''' dic = {"name":"jin","age":18,"sex":"male"} dic2 = {"name":"alex","weight":75} dic2.update(dic) # # print(dic) print(dic2) dic1 = {'age': 18, 'name': 'jin', 'sex': 'male',}
#查
''' print(dic1.keys(),type(dic1.keys())) print(dic1.values()) print(dic1.items()) ''' # for i in dic1: # print(i) #for i in dic1.keys(): # print(i) # for i in dic1.values(): # print(i)
for k,v in dic1.items(): print(k,v) # v1 = dic1['name'] # print(v1) # v2 = dic1['name1'] # 报错 # print(v2) print(dic1.get('name1','没有这个键'))#想得到一个键值首选,不会报错
3.数值交换
#a,b = 1,2 #print(a,b) # a = 1 # b = 2 # a,b = b,a # print(a,b) # a,b = [1,2],[2,3] # a,b = (1,2) # print(a,b)
二:字典的嵌套
1.
dic = { 'name':['alex','wusir','taibai'], 'py9':{ 'time':'1213', 'learn_money':19800, 'addr':'CBD', }, 'age':21 } # # dic['age'] = 56 #print(dic['name']) #dic['name'].append('ritian') # l = [1,2,'wusir'] # l[2] = l[2].upper() # dic['name'][1] = dic['name'][1].upper() #print(dic) female : 6 dic['py9']['female'] = 6 print(dic)
2.以前知识点的一个小练习
# fhdklah123rfdj12fdjsl3 ' 123 12 13'
''' content = input("请输入:").strip() for i in content: if i.isalpha(): content = content.replace(i,' ') print(content) l = content.split() print(l) print(len(l))
3.split()方法补充
''' l = " 11 11 11" l = l.split() print(l) #当不带参数时,默认是以空格作为参数,不管空格在哪,或者有几个 全部被干掉了 ''' str="hello boy<[www.doiido.com]>byebye" str=str.split("[")[1].split("]")[0] print(str) #'www.doiido.com' str=str.split("[")[1].split("]")[0].split(".") print(str) #['www', 'doiido', 'com'] '''