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python入门基础知识(代码)

python入门基础知识(代码)

作者: 地表最强程序员小白 | 来源:发表于2017-11-18 23:21 被阅读5次
    import abc as aa                      #导入模块
    from aifc import _read_long as fd
    from datetime import *
    import json
    import unittest
    print("Hello World!")#打印Hello World!
    i=5                  #直接使用变量 无需声明
    s="hello"
    print(str(i)+"."+s)  #函数str将其他类型转成字符串
    print(s.title()+" "+s.lower()+" "+s.upper())
    print("  hello"+" "+"  hello".lstrip())  #lstrip函数删除左边空格  类似还有rstrip strip
    print(3/2)         #python3里 3/2等于1.5
    players=['kobe', 'james', 'harden']   #列表
    print(players)
    print(players[1])       #类似于数组,包括索引从0开始
    players[2]='westbrook'
    print(players)
    players.append('harden') #在列表末尾添加
    print(players)
    players.insert(2,'simons') #在列表中插入
    print(players)
    del players[3]   #删除
    print(players)
    p=players.pop()   #类似栈的弹出
    q=players.pop()
    print(p+" "+q)
    d=players.pop(1)   #指定位置弹出
    print(d)
    players.remove('kobe')   #删除
    print(players)
    cars=['bmw', 'audi', 'toyota', 'subaru']
    cars.sort()     #排序
    print(cars)
    cars.sort(reverse=True)
    print(cars)
    print(sorted(cars))      #临时排序
    print(cars)
    cars.reverse()           #倒叙
    print(cars)
    print(len(cars))      #列表长度
    for car in cars:      #for循环
        print(car)
    for a in range(5):     #生成0-4的数字
        print(a)
    numbers=list(range(4))  #函数list将range产生的数字转化为列表
    print(numbers)
    print(numbers[1:3])    #列表的切片
    print(numbers[2:])
    copynum=numbers[:]     #复制列表要使用切片
    print(copynum)
    dimensions=(200, 50)   #元组  无法直接给元组的元素赋值
    print(dimensions[0])
    dimensions=(200, 100)  #要改变元组元素  要重新定义整个元组
    print(dimensions)
    print('bmw' in cars)         #是否包含在列表中
    print('audi' not in cars)
    people_0={'sex':'man', 'name':'kobe'}    #字典
    print(people_0['sex'])
    people_1={}              #创建空字典
    people_1['height']=167       #添加键值对
    people_1['weight']=58
    print(people_1)
    people_1['height']=226
    print(people_1)
    del people_1['height']          #删除键值对
    print(people_1)
    for k,v in people_0.items():    #循环遍历
        print(k+" "+v)
    for k in people_1.keys():
        print(k)
    man_1={'money':12, "house":2}
    man_2={'money':22, "house":4}
    man_3={'money':18, "house":0}
    men=[man_1, man_2, man_3]            #字典列表
    for m in men:
        print(m['money'],m['house'])
        print(m.items())
        print(m)
    cars={                               #字典中存储列表
        'type':'bus',
        'rate':50,
        'people':['kobe','james','simos']
    }
    for car in cars.items():
        print(car)
    for p in cars['people']:
        print(p)
    nba={                              #字典中嵌套字典
        'thunder':{
            'pg':'westbrook',
            'sg':'roberson',
            'sf':'geoger',
            'pf':'antony',
            'c':'adams',
        },
        '76ers':{
            'pg':'simons',
            'sg':'redick',
            'sf':'covington',
            'pf':'saric',
            'c':'embid',
        },
    }
    n=0
    while n<=10:
        print(n)
        n+=1
    n=0
    while n<10:
        print(n)
        n+=2
        if n==4:
            continue
        if n==6:
            break
    for a in nba.items():       #嵌套字典的遍历
        for b in a:
            print(b)
    #msg=input('please input a message: ')           #字符串的输入
    #print(msg)
    #num=input('please input a number: ')            #数字的输入
    #num=int(num)
    #print(num)
    def hello():                 #定义和调用函数
        print("hello world")
    hello()
    def pri(msg):
        print(msg)
    pri('Hello')
    def test(a,b):
        print(a,b)
    test(b='hh',a='aa')            #关键字实参
    def te(a,b='abc'):             #参数默认值
        return(a,b)
        print(a,b)
    te('gg')
    te('gg','kk')
    def rr(a):                     #函数无需声明返回值
        return a+5
    cc=rr(5)
    print(cc)
    def list(m):                 #传入列表
        for mm in m:
            print(mm)
    list(men)
    list(men[:])                 #禁止函数对列表的修改 即传入切片
    def abc(*a):                 #可传入任意数量实参
        for k in a:
            print(k)
    abc(1,2,5,8)
    class dog():                     #类
        """文档注释"""
        def __init__(self,name,sex):        #相当于构造器 注意前后是两个下划线
            self.name=name                  #self相当于java的this
            self.sex=sex
        def fun(self):
            print("I an funny")
    mydog=dog('kevin','woman')
    print(mydog.name+" "+mydog.sex)
    mydog.fun()
    class bigdog(dog):
        def __init__(self,name,sex,age):
            super().__init__(name,sex)       #调用父类构造器
            self.age=age
        def fun(self):                       #重写父类方法
            print("I am happy")
    mybigdog=bigdog('kevin','woman',28)
    print(mybigdog.age)
    mybigdog.fun()
    with open('abc.txt')as afile:          #打开文件
        contents=afile.read()
        print(contents.strip())
    with open('abc.txt')as afile:
        for line in afile:
            print(line.strip())
    with open('abc.txt')as afile:
        s=""
        for line in afile:
            s+=line.strip()
        print(s)
    with open('pi.txt')as pifile:                   #写入文件
        content=pifile.read().strip()
        print(content[:100])
    with open('gg.txt','w')as myfile:
        myfile.write("I love you")
    with open('gg.txt','a')as myfile:
        myfile.write("\nhaha")
    try:                                #异常处理
        print(5/0)
    except ZeroDivisionError:
        print('no you can not do this')
    else:
        pass
    with open('test.json','w')as mytest:   #存储数据
        json.dump("哈哈哈",mytest)
    with open('test.json')as mytest:
        str=json.load(mytest)
        print(str)
    class testme(unittest.TestCase):
        def test_fu(self):
            sss=te("kk")
            self.assertEqual(sss,'kkabc')
    unittest.main()
    

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