浅谈python的深浅拷贝以及fromkeys的用法

# lst = ["alex","dsb",'wusir','xsb']
# s = "".join(lst)
# print(s) #alexdsbwusirxsb

# s = "alex_dsb_wusir_xsb"
# lst = s.split("_") #列表
# print(lst)

# print("*".join("周润发")) #用迭代的方式进行拼接
# #周*润*发

# lst = ["篮球","排球","乒乓球","足球","电子竞技","台球"]
# for el in lst:
# lst.remove(el)
# print(lst)#['排球', '足球', '台球']

#lst = ["篮球","排球","乒乓球","足球","电子竞技","台球"]
# for i in range(len(lst)): #0,1,2,3,4
# lst.pop(0)
# print(lst) #[] #永远删索引是0元素
# for i in range(len(lst)):
# lst.pop()
# print(lst) #[] #从最后一个删

# d = dict.fromkeys("张无忌","赵敏") #创建字典
# print(d)#{'张': '赵敏', '无': '赵敏', '忌': '赵敏'}

# dic = {}
# d = dic.fromkeys("风扇哥","很困")
# print(dic)# {}
# print(d)#{'风': '很困', '扇': '很困', '哥': '很困'}

d = dict.fromkeys("胡辣汤",[])
print(d)#{'胡': [], '辣': [], '汤': []}
# print(id(d["胡"]))#1797375051912
# print(id(d["辣"]))#1797375051912
# print(id(d["汤"]))#1797375051912
#说明这几个还是同一个[] 所以对其中一个进行改变别的也进行相应的改变
# d["胡"] .append("湖南特色")
# print(d)#{'胡': ['湖南特色'], '辣': ['湖南特色'], '汤': ['湖南特色']}

# lst1 = ["胡辣汤","麻辣香锅","灌汤包","油泼面"]
# lst2 = lst1 #并没有产生新对象.只是一个指向(内存地址)的赋值
# print(id(lst1))#2253612239048
# print(id(lst2))#2253612239048
# lst1.append("葫芦娃")
# print(lst1)#['胡辣汤', '麻辣香锅', '灌汤包', '油泼面', '葫芦娃']
# print(lst2)#['胡辣汤', '麻辣香锅', '灌汤包', '油泼面', '葫芦娃']

# lst1 = ["胡辣汤","麻辣香锅","灌汤包","油泼面"]
# lst2 = lst1.copy() #拷贝,抄作业,可以帮我们创建新的对象,和原来一模一样,浅拷贝
# print(id(lst1))#2232732993736
# print(id(lst2))#2232732993672
#
# lst1.append("葫芦娃")
# print(lst1)
# print(lst2)

# lst1 = ["胡辣汤", "灌汤包", "油泼面", "麻辣香锅", ["长白山", "白洋淀", "黄鹤楼"]]
# lst2 = lst1.copy() #浅拷贝,只拷贝第一层内容
#
# print(id(lst1))#1199044806792
# print(id(lst2))#1199044806984
# print(lst1)
# print(lst2)
#
# lst1[4].append("葫芦娃")
# print(lst1)
# print(lst2)

#深拷贝 需要引入一个模块
import copy

lst1 = ["胡辣汤", "灌汤包", "油泼面", "麻辣香锅", ["长白山", "白洋淀", "黄鹤楼"]]
lst2 = copy.deepcopy(lst1)#深拷贝 对象内部的所有内容都要复制一份.深度克隆 原型模式
print(id(lst1))#2150506176840
print(id(lst2))#2150506178120

print(lst1)#['胡辣汤', '灌汤包', '油泼面', '麻辣香锅', ['长白山', '白洋淀', '黄鹤楼']]
print(lst2)#['胡辣汤', '灌汤包', '油泼面', '麻辣香锅', ['长白山', '白洋淀', '黄鹤楼']]
lst1[4].append("葫芦娃")
print(lst1)#['胡辣汤', '灌汤包', '油泼面', '麻辣香锅', ['长白山', '白洋淀', '黄鹤楼', '葫芦娃']]
print(lst2)#['胡辣汤', '灌汤包', '油泼面', '麻辣香锅', ['长白山', '白洋淀', '黄鹤楼']]