python基础：list,map,open()文件读写

Myth丶恋晨 2022-03-21 16:20 218阅读 0赞

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# 1， list #

list.py

#定义 list集合： 方法1
    bob=['bob,smith', 23, 30000, 'software']
    sue=['sue,jones', 34, 40000, 'hardware']
    people=[bob,sue]
    
    #定义 list集合： 方法2
    names=  ["name",    "age", "pay", "job"]
    values1=["bob smith", 42,  30000, "software"]
    values2=["sue jones", 34,  4000,  'hardware']
    kvlist1=list( zip(names,values1) )#[('name', 'bob smith'), ('age', 42), ('pay', 30000), ('job', 'software')]
    print(kvlist1[0][1]) #bob smith
    kvlist2=list( zip(names,values2) )#[('name', 'sue jones'), ('age', 34), ('pay', 40000), ('job', 'hardware')]
    print(kvlist2[0][1]) #sue jones
    
    #取出值
    name1=bob[0].split(',')[-1]
    print("bob last name is ",name1) #bob last name is  smith
    
    age= (sue[1]*2 )
    print("sue age is",age)#sue age is 68
    
    #从大集合中取出值
    bobname=people[0][0] #bob,smith
    print(bobname)
    
    #遍历集合
    for per in people:
        print(per[0],",", per[1],",", per[2]) # bob,smith , 23 , 30000     sue,jones , 34 , 40000
    
    for per in people: per[1]*=2
    for per in people: print(per[1])# (23, 34) ==> 46, 68
    
    pays=[per[2] for per in people ]
    print(pays)# [30000,40000]
    print("--pay 的总和 ", sum( pays))  #70000
    
    pays=map( (lambda x: x[2]) , people)
    print( pays ) # <map object at 0x00C96050>
    print(  list(pays) ) #[30000, 40000]
    
    
    #列表的扩展
    people.append(['tom willy', 45, 80000])
    for per in people: print(per[0])
    
    #使用下标
    name, age ,pay =range(3)
    print(name, age, pay) #0 1 2
    print( bob[name] ) #bob,smith
    
    ############################################
    #定义kv对
    bob=[['name','bob smith'], ['age',32], ['pay',80000]]
    sue=[['name','sue jones'], ['age',56],  ['pay',70000]]
    people=[bob, sue]
    
    
    #遍历list
    for per in people:
        print(per[0][1]) #bob smith    sue jones
    
    names= [per[0][1]  for per in people ]
    print(names) #['bob smith', 'sue jones']
    
    for per in people:
        for (name,value)  in  per: #['name','bob smith']  ['name','sue jones']
            if name=='name': print(value)

# 2， map #

map.py

#定义字典：方法1
    bob={"name":"bob smith", "age":42, "pay":30000, "job":"dev"}
    sue={"name":"sue jones", "age":32, "pay":50000,  "job":"hdw"}
    
    #定义字典：方法2
    bob=dict(name="bob smith", age=42, pay=3000,  job="dev")
    sue=dict(name="sue jones", age=32,  pay=50000, job="hdw")
    
    #定义字典：方法3
    bob={}
    bob["name"]="bob smith"
    bob["age"]=42
    bob["pay"]="dev"
    
    #定义字典：f\方法4
    fields=("name", "age", "job", "pay")
    record=dict.fromkeys(fields, "?")
    print(record)#{'name': '?', 'age': '?', 'job': '?', 'pay': '?'}
    
    #定义字典：方法4
    names=["name","age", "pay", "job"]
    values=["bob smith", 42, 30000, "dev"]
    kvmap=dict(zip ( names, values)) #{'name': 'bob smith', 'age': 42, 'pay': 30000, 'job': 'dev'}
    print(kvmap["name"])#bob smith
    
    #取出字典的值：方法1
    print(bob["name"], ",", bob['age']) #bob smith  42
    print(bob["name"]) #bob smith
    print(bob["name"].split()[-1]) #smith
    print(sue["pay"]) # 5000
    
    #取出字典的值: 方法2
    msg1="name=>%s, age=%s"%(dict["name"], bob["age"])
    msg2="name=>%(name)s, age=>%(age)s"%bob
    msg3="name=>{name}, age={age}".format(**bob)
    print(msg1)#name=>lisi, age=>32
    print(msg2)#name=>lisi, age=>32
    print(msg3)#name=>lisi, age=>32
    
    
    # map中嵌套list
    bob={
        "name":{"first":"bob",  "last":"smith"},
        "age":32,
        "job":["software","writing"],
        "pay":[40000, 50000]
    }
    print(bob["name"]["first"]) #bob
    print(bob["pay"][1])#50000
    for job in bob["job"]: print(job) #software  writing
    
    bob["job"].append("hardware")
    for job in bob["job"]: print(job) #software  writing hardware
    
    #map 嵌套map
    people={}
    people["bob"]=bob
    people["sue"]=sue
    for value in people.values():#{'name': {'first': 'bob', 'last': 'smith'}, 'age': 32, 'job': ['software', 'writing', 'hardware'], 'pay': [40000, 50000]}
                                 #{'name': 'sue jones', 'age': 32, 'pay': 50000, 'job': 'hdw'}
       for key in value.keys():
           print(key) #name, age, job, pay
    
    
    for key in people.keys():
        print(key, people[key]) #sue {'name': 'sue jones', 'age': 32, 'pay': 50000, 'job': 'hdw'}
    for item in people.items():
        print(item) #('sue', {'name': 'sue jones', 'age': 32, 'pay': 50000, 'job': 'hdw'})

# 3， map和list互相嵌套 #

list\_map.py

#map
    bob={"name":"bob jones", "age":32, "pay":30000, "job":"dev"}
    sue={"name":"sue smith", "age":42, "pay":40000, "job":"dev"}
    #list
    people=[bob, sue]
    db={"bob":bob, "sue":sue}
    
    #遍历
    for per in people:
        print(per["name"], per["age"], per["pay"], sep=", ") #bob jones, 32, 30000      sue smith, 42, 40000
    
    for per in people:
        if per["name"]=="bob jones":
            print(per["pay"]) # 3000
    
    
    names=[ per["name"] for per in people ]
    print(names)#['bob jones', 'sue smith']
    
    res=map( ( lambda x:x["name"]), people)
    print(list(res))#['bob jones', 'sue smith']
    
    sumpay=sum( per["pay"] for per in people)
    print(sumpay)# 70000
    
    names=[per["name"] for per in people if per["age"] >40 ]
    print(names) #['sue smith']
    names2=(per["name"] for per in people if per["age"]> 40 )
    print(next(names2)) #sue smith
    
    pays=[  (per["pay"]*2  if per["age"]> 40  else per["pay"] )     for per in people ]
    print(pays) #[30000, 80000]

# 4， 文件读写 #

read\_write.py

fileName="py-db.txt"
    
    #保存数据
    def save(db, fileName=fileName):
        output = open(fileName, "w")# w, r
        for per in db:
            print(per,  file=output)
            for(name, value) in db[per].items():
                print(name,value, sep=",",file=output)
            print("kv-over",file=output)
    
        print("db-over",file=output)
        output.close()
    
    def read(fileName=fileName):
        inputstr=open(fileName)
        import sys
        sys.stdin=inputstr
    
        key=input()
        print(key)
    
        while(key  != "db-over"):
            field=input()
            while field != "kv-over":
                name, value= field.split(",")
                print("读入的数据=> ",name, value)
                field=input()
            key = input()
            print(key)
    
    def read2(fileName=fileName):
        inputstr=open(fileName)
        import sys
        sys.stdin=inputstr
    
        db={}
        key=input()
    
        while(key  != "db-over"):
            person={}
            field=input()
            while field != "kv-over":
                name, value= field.split(",")
                person[name]=value
                field=input()
            db[key]=person
            key = input()
        print("db==== " , db)
        return db
    
    if __name__== "__main__":
        #from chapter1.res.list_map import db
        # save(db)
        read2()

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