从Zero到Hero,一文掌握Python关键代码

# 01基础篇

# 变量

 #int
 one=1
 some_number=100

 print("one=",one)   #print type1
 print("some_number=",some_number)   #python3 print need add ()

 """output
 one= 1
 some_number= 100
 """

 #booleans
 true_boolean=True
 false_boolean=False

 print("true_boolean:",true_boolean)
 print("False_boolean;",false_boolean)

 """output
 true_boolean: True
 False_boolean; False
 """

 #string
 my_name="leizeling"

 print("my_name:{}".format(my_name))    #print type2

 """output
 true_boolean: True
 False_boolean; False
 """

#float
book_price=15.80

print("book_price:{}".format(book_price))

"""output
book_price:15.8
"""

# 控制流：条件语句

 #if
 if True:
     print("Hollo Python if")
 if 2>1:
     print("2 is greater than 1")

 """output
 Hollo Python if
 2 is greater than 1
 """

 #if……else
 if 1>2:
     print("1 is greater than 2")
 else:
     print("1 is not greater than 2")

 """output
 true_boolean: True
 False_boolean; False
 """

#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
"""

 #for
 for i in range(1,11):#range(start,end,step),not including end
     print(i)

 """output
 1
 2
 3
 4
 5
 6
 7
 8
 9
 10
 """

# 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']
"""

 #add item to list
 bookshelf=[]
 bookshelf.append("The Effective Engineer")
 bookshelf.append("The 4 Hour Work Week")
 print(bookshelf[0])
 print(bookshelf[1])

 """output
 The Effective Engineer
 The 4 Hour Work Week
 """

# 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
"""

 #dictionary add item
 dictionary_tk["age"]=24
 print(dictionary_tk)

 """output
 {'nationality': 'Brazilian', 'nickname': 'Tk', 'name': 'Leandro', 'age': 24}
 """

#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
"""

 #哈希数据结构（iteration of dictionary）
 dictionary_tk={"name":"Leandro","nickname":"Tk","nationality":"Brazilian"}
 for key in dictionary_tk:  #the attribute can use any name,not only use "key"
     print("%s:%s"%(key,dictionary_tk[key]))
 print("===================")
 for key,val in dictionary_tk.items():  #attention:this is use dictionary_tk.items().not direct use dictionary_tk
     print("{}:{}".format(key,val))

 """output
 nationality:Brazilian
 nickname:Tk
 name:Leandro
 ===================
 nationality:Brazilian
 nickname:Tk
 name:Leandro
 """

# 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

 #公开实例变量
 class Person:
     def __init__(self,first_name):
         self.first_name=first_name
 tk=Person("TK")
 print(tk.first_name)
 tk.first_name="Kaio"
 print(tk.first_name)

 """output
 TK
 Kaio
 """

#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
"""

 #私有方法
 class Person:
     def __init__(self,first_name,age):
         self.first_name=first_name
         self._age=age
     def _show_age(self):
         return self._age
     def show_age(self):
         return self._show_age() #此处的self不要少了
 tk=Person("TK",24)
 print(tk.show_age())

 """output
 24
 """

 #继承
 class Car:#父类
     def __init__(self,number_of_wheels,seating_capacity,maximum_velocity):
         self.number_of_wheels=number_of_wheels
         self.seating_capacity=seating_capacity
         self.maximum_velocity=maximum_velocity
 class ElectricCar(Car):#派生类
     def __init(self,number_of_wheels_1,seating_capacity_1,maximum_velocity_1):
         Car.__init__(self,number_of_wheels_1,seating_capacity_1,maximum_velocity_1)  #利用父类进行初始化

 my_electric_car=ElectricCar(4,5,250)
 print(my_electric_car.number_of_wheels)
 print(my_electric_car.seating_capacity)
 print(my_electric_car.maximum_velocity)

 """output
 4
 5
 250
 """

注：从机器之心转载