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  • 从Zero到Hero,一文掌握Python关键代码

    # 01基础篇

    # 变量

     1 #int
     2 one=1
     3 some_number=100
     4 
     5 print("one=",one)   #print type1
     6 print("some_number=",some_number)   #python3 print need add ()
     7 
     8 """output
     9 one= 1
    10 some_number= 100
    11 """
     1 #booleans
     2 true_boolean=True
     3 false_boolean=False
     4 
     5 print("true_boolean:",true_boolean)
     6 print("False_boolean;",false_boolean)
     7 
     8 """output
     9 true_boolean: True
    10 False_boolean; False
    11 """
    1 #string
    2 my_name="leizeling"
    3 
    4 print("my_name:{}".format(my_name))    #print type2
    5 
    6 """output
    7 true_boolean: True
    8 False_boolean; False
    9 """
    #float
    book_price=15.80
    
    print("book_price:{}".format(book_price))
    
    """output
    book_price:15.8
    """

    # 控制流:条件语句

     1 #if
     2 if True:
     3     print("Hollo Python if")
     4 if 2>1:
     5     print("2 is greater than 1")
     6 
     7 """output
     8 Hollo Python if
     9 2 is greater than 1
    10 """
     1 #if……else
     2 if 1>2:
     3     print("1 is greater than 2")
     4 else:
     5     print("1 is not greater than 2")
     6 
     7 """output
     8 true_boolean: True
     9 False_boolean; False
    10 """
    #if……elif……else
    if 1>2:
        print("1 is greater than 2")
    elif 1<2:
        print("1 is not greater than 2")
    else:
        print("1 is equal to 2")
    
    """output
    1 is not greater than 2
    """

    # 循环/迭代器

    #while
    num=1
    while num<=10:
        print(num)
        num+=1
    
    """output
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    """
     1 #for
     2 for i in range(1,11):#range(start,end,step),not including end
     3     print(i)
     4 
     5 """output
     6 1
     7 2
     8 3
     9 4
    10 5
    11 6
    12 7
    13 8
    14 9
    15 10
    16 """

    # 02列表:数组数据结构

    #create  integers list
    my_integers=[1,2,3,4,5]
    print(my_integers[0])
    print(my_integers[1])
    print(my_integers[4])
    
    """output
    1
    2
    5
    """
    #create str list
    relatives_name=["Toshiaki","Juliana","Yuji","Bruno","Kaio"]
    print(relatives_name)
    
    """output
    ['Toshiaki', 'Juliana', 'Yuji', 'Bruno', 'Kaio']
    """
     1 #add item to list
     2 bookshelf=[]
     3 bookshelf.append("The Effective Engineer")
     4 bookshelf.append("The 4 Hour Work Week")
     5 print(bookshelf[0])
     6 print(bookshelf[1])
     7 
     8 """output
     9 The Effective Engineer
    10 The 4 Hour Work Week
    11 """

    # 03字典:键-值数据结构

    #dictionary struct
    dictionary_example={"key1":"value1","key2":"value2","key3":"value3"}
    dictionary_example
    
    """output
    {'key1': 'value1', 'key2': 'value2', 'key3': 'value3'}
    """
    #create dictionary
    dictionary_tk={"name":"Leandro","nickname":"Tk","nationality":"Brazilian"}
    print("My name is %s"%(dictionary_tk["name"]))
    print("But you can call me %s"%(dictionary_tk["nickname"]))
    print("And by the waay I am {}".format(dictionary_tk["nationality"]))
    
    """output
    My name is Leandro
    But you can call me Tk
    And by the waay I am Brazilian
    """
    1 #dictionary add item
    2 dictionary_tk["age"]=24
    3 print(dictionary_tk)
    4 
    5 """output
    6 {'nationality': 'Brazilian', 'nickname': 'Tk', 'name': 'Leandro', 'age': 24}
    7 """
    #dictionayr del item
    dictionary_tk.pop("age")
    print(dictionary_tk)
    
    """output
    {'nationality': 'Brazilian', 'nickname': 'Tk', 'name': 'Leandro'}
    """

    # 04迭代:数据结构中的循环

    #iteration of list
    bookshelf=["The Effective Engineer","The 4 hours work week","Zero to One","Lean Startup","Hooked"]
    for book in bookshelf:
        print(book)
    
    """output
    The Effective Engineer
    The 4 hours work week
    Zero to One
    Lean Startup
    Hooked
    """
     1 #哈希数据结构(iteration of dictionary)
     2 dictionary_tk={"name":"Leandro","nickname":"Tk","nationality":"Brazilian"}
     3 for key in dictionary_tk:  #the attribute can use any name,not only use "key"
     4     print("%s:%s"%(key,dictionary_tk[key])) 
     5 print("===================")
     6 for key,val in dictionary_tk.items():  #attention:this is use dictionary_tk.items().not direct use dictionary_tk
     7     print("{}:{}".format(key,val))
     8 
     9 """output
    10 nationality:Brazilian
    11 nickname:Tk
    12 name:Leandro
    13 ===================
    14 nationality:Brazilian
    15 nickname:Tk
    16 name:Leandro
    17 """

    # 05 类和对象

    #define class
    class Vechicle:
        pass
    #create instance
    car=Vechicle()
    print(car)
    
    ""output
    <__main__.Vechicle object at 0x000000E3014EED30>
    """
    #define class
    class Vechicle(object):#object is a base class
        def __init__(self,number_of_wheels,type_of_tank,seating_capacity,maximum_velocity):
            self.number_of_wheels=number_of_wheels
            self.type_of_tank=type_of_tank
            self.seating_capacity=seating_capacity
            self.maximum_velocity=maximum_velocity
        def get_number_of_wheels(self):
            return self.number_of_wheels
        def set_number_of_wheels(self,number):
            self.number_of_wheels=number
    
    #create instance(object)
    tesla_models_s=Vechicle(4,"electric",5,250)
    tesla_models_s.set_number_of_wheels(8)#方法的调用显得复杂
    tesla_models_s.get_number_of_wheels()
    
    """output
    8
    """
    #use @property让方法像属性一样使用
    #define class
    class Vechicle_1(object):#object is a base class
        def __init__(self,number_of_wheels,type_of_tank,seating_capacity,maximum_velocity):#first attr must is self,do not input the attr
            self._number_of_wheels=number_of_wheels   ###属性名和方法名不要重复
            self.type_of_tank=type_of_tank
            self.seating_capacity=seating_capacity
            self.maximum_velocity=maximum_velocity
        @property #读属性
        def number_of_wheels(self):
            return self._number_of_wheels
        @number_of_wheels.setter #写属性
        def number_of_wheels(self,number):
            self._number_of_wheels=number
        def make_noise(self):
            print("VRUUUUUUUM")
    
    tesla_models_s_1=Vechicle_1(4,"electric",5,250)
    print(tesla_models_s_1.number_of_wheels)
    tesla_models_s_1.number_of_wheels=2
    print(tesla_models_s_1.number_of_wheels)
    print(tesla_models_s_1.make_noise())
    
    """output
    4
    2
    VRUUUUUUUM
    None
    """

    # 06封装:隐藏信息

     1 #公开实例变量
     2 class Person:
     3     def __init__(self,first_name):
     4         self.first_name=first_name
     5 tk=Person("TK")
     6 print(tk.first_name)
     7 tk.first_name="Kaio"
     8 print(tk.first_name)
     9 
    10 """output
    11 TK
    12 Kaio
    13 """
    #私有实例变量
    class Person:
        def __init__(self,first_name,email):
            self.first_name=first_name
            self._email=email
        def get_email(self):
            return self._email
        def update_email(self,email):
            self._email=email
    tk=Person("TK","tk@mail.com")
    tk.update_email("new_tk@mail.com")
    print(tk.get_email())
    
    """output
    new_tk@mail.com
    """
    #公有方法
    class Person:
        def __init__(self,first_name,age):
            self.first_name=first_name
            self._age=age
        def show_age(self):
            return self._age
    tk=Person("TK",24)
    print(tk.show_age())
    
    """output
    24
    """
     1 #私有方法
     2 class Person:
     3     def __init__(self,first_name,age):
     4         self.first_name=first_name
     5         self._age=age
     6     def _show_age(self):
     7         return self._age
     8     def show_age(self):
     9         return self._show_age() #此处的self不要少了
    10 tk=Person("TK",24)
    11 print(tk.show_age())
    12 
    13 """output
    14 24
    15 """
     1 #继承
     2 class Car:#父类
     3     def __init__(self,number_of_wheels,seating_capacity,maximum_velocity):
     4         self.number_of_wheels=number_of_wheels
     5         self.seating_capacity=seating_capacity
     6         self.maximum_velocity=maximum_velocity
     7 class ElectricCar(Car):#派生类
     8     def __init(self,number_of_wheels_1,seating_capacity_1,maximum_velocity_1):
     9         Car.__init__(self,number_of_wheels_1,seating_capacity_1,maximum_velocity_1)  #利用父类进行初始化
    10 
    11 my_electric_car=ElectricCar(4,5,250)
    12 print(my_electric_car.number_of_wheels)
    13 print(my_electric_car.seating_capacity)
    14 print(my_electric_car.maximum_velocity)
    15 
    16 """output
    17 4
    18 5
    19 250
    20 """

    注:从机器之心转载

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  • 原文地址:https://www.cnblogs.com/ys99/p/9128775.html
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