python：字典

# 容器的通用操作# 1、判断元素是否在容器中元素 in 容器# 2、获取容器长度len(容器)# 3、遍历容器for x in 容器#字典key值重复后面会覆盖前面的dict_one{key1:value1,key2:value2,key3:3,key4:4}dict_twodict(kk1vv1,kk2vv2,kk33)# 一、判断key是否在字典中print(判断key是否在字典中)flag1key1indict_oneprint(fkey1是否在字典中{flag1})flag2kkkindict_twoprint(fkkk是否在字典中{flag2})# 结果:# key1是否在字典中True# kkk是否在字典中False# 二、遍历print(遍历)# 方式一只遍历key值print(方式一只遍历key值)foritemindict_one:print(item)# 结果:# key1# key2# key3# key4# 方式二遍历value值print(方式二遍历value值)forvalueindict_one.values():print(value)# 结果:# value1# value2# 3# 4# 方式三遍历字典对象key,valueprint(方式三遍历字典对象key,value)forkey,valueindict_two.items():print(fkey为{key}- value为{value})# 结果:# key为kk1 - value为vv1# key为kk2 - value为vv2# key为kk3 - value为3# 三、添加\修改print(添加\修改)dict_three{name:zhangsan,sex:1}print(f添加前{dict_three})dict_three[age]20#key值存在修改不存在添加dict_three[sex]2#key值存在修改不存在添加print(f添加后{dict_three})# 结果:# 添加前dict_three{name: zhangsan, sex: 1}# 添加后dict_three{name: zhangsan, sex: 2, age: 20}dict_three2{name:zhangsan2,sex:100}#key值存在修改不存在添加dict_three2.update({name:改成汉字张三,add:updateadd})print(f{dict_three2})# 结果: dict_three2{name: 改成汉字张三, sex: 100, add: updateadd}# 四、删除print(删除)dict_fourdict(name李四,sex0,age18)print(f删除前{dict_four})dict_four.pop(name)#删除key存在的字典#dict_four.pop(aaaa) #删除key不存在的字典会报错print(f删除后{dict_four})deldict_four[age]#del删除元素print(fdel删除后{dict_four})# 结果:# 删除前dict_four{name: 李四, sex: 0, age: 18}# 删除后dict_four{sex: 0, age: 18}# del删除后dict_four{sex: 0}# 五、查print(查)dict_five{aa:bb,aaaa:bbbb}print(f字典查找{dict_five[aaaa]})# 结果: 字典查找bbbb# 六、字典推导式print(字典推导式)numsrange(97,100)chrs[a,b,c,d]dict_six{key:valueforkeyinnumsforvalueinchrsifkeyord(value)}#ord方法字符转数字print(f字典推导式生成的字典{dict_six})# 结果: 字典推导式生成的字典dict_six{97: a, 98: b, 99: c}结果判断key是否在字典中key1是否在字典中Truekkk是否在字典中False遍历方式一只遍历key值key1key2key3key4方式二遍历value值value1value234方式三遍历字典对象key,valuekey为kk1 - value为vv1key为kk2 - value为vv2key为kk3 - value为3添加\修改添加前dict_three{‘name’: ‘zhangsan’, ‘sex’: ‘1’}添加后dict_three{‘name’: ‘zhangsan’, ‘sex’: ‘2’, ‘age’: 20}dict_three2{‘name’: ‘改成汉字张三’, ‘sex’: ‘100’, ‘add’: ‘updateadd’}删除删除前dict_four{‘name’: ‘李四’, ‘sex’: 0, ‘age’: 18}删除后dict_four{‘sex’: 0, ‘age’: 18}del删除后dict_four{‘sex’: 0}查字典查找bbbb字典推导式字典推导式生成的字典dict_six{97: ‘a’, 98: ‘b’, 99: ‘c’}