Python--字典操作
字典的增删改查及遍历
1 info = { 2 "stu3":"yuanyuan", 3 "stu1":"tianjie", 4 "stu2":"wangxinlin" 5 } 6 print(type(info)) #输出类型 7 print(info) 8 print(info["stu1"]) #查找 条件：适用于确定有该键值,没有键值时报错 9 print(info.get("stu00")) #没有时返回None 10 print(info.get("stu1")) #有就返回value 11 12 print("stu02" in info) #判断是否存在该数据，如果存在返回True，不存在返回False 13 # info.has_key("stu1") # 适用于py2 14 15 info["stu2"] = "fenglubei" #修改 16 print(info) 17 info["stu4"] = "wangxinlin" #没有该键时新增 18 print(info) 19 20 del info["stu1"] #删除 21 print(info) 22 23 info.pop("stu2") #删除特定键值 24 print(info) 25 26 info.popitem() #随机删 27 print(info) 28 29 #字典嵌套 30 shuqike = { 31 "gongsi":{ 32 "kaifa":["ma","jiaming","jiao","yuan","yaqiong","zhendong"], 33 "yunwei":["yecai","majin"] 34 }, 35 "SJS":{ 36 "kaifa":["cong","jiang"], 37 "yunwei":["feng","tian","xinlin","yuanyuan"] 38 } 39 } 40 print(shuqike) 41 42 #查 43 print(shuqike["gongsi"]["kaifa"][2]) 44 print(shuqike["SJS"]["yunwei"][2]) 45 46 #改 47 shuqike["gongsi"]["kaifa"][2] = "zhen" 48 print(shuqike) 49 50 #增加 51 shuqike["gongsi"]["jiagou"] = ["hou","peng"] 52 print(shuqike) 53 54 #高级 55 zimu = { 56 "大写":["A","B","C"], 57 "小写":["a","b","c"] 58 } 59 print(zimu.keys()) #获取列表里的所有key 60 print(zimu.values()) #获取列表里的所有value 61 62 # setdefault,在字典里取值，当能取到值时就不动字典，当取不到值时，创建一个 63 zimu.setdefault("qita", [1,2,3]) 64 zimu.setdefault("大写", ["D"]) 65 print(zimu) 66 67 #update,存在交叉，更新值，不存在键则新增 68 b = { 69 "小写":"fff", 70 1:2, 71 3:4 72 } 73 zimu.update(b) 74 print(zimu) 75 76 print(zimu.items()) #字典转列表 77 78 c = dict.fromkeys([6,7,8],"test") #创建一个字典，key为678，值都为test 79 print(c) 80 81 d = dict.fromkeys([1,2,3],[1,{"name":"tinajie"},333]) 82 print(d) 83 d[3][1]["name"] = "yuanyuan" #都改，并不是只改一个 84 print(d) 85 86 #字典的遍历 87 for i in zimu: 88 print(i) #只打印key 89 print(i,zimu[i]) 90 91 for k,v in zimu.items(): #效率低于上面那种，因为要转成列表 92 print(k,v)
