"""
题目：将一个列表的数据复制到另一个列表中。
"""
import copy
def validate(a, b):
"""
验证复制结果
:param a:
:param b:
:return:
"""
print("a =", a)
print("b =", b)
print("a == b is", a == b)
print("id(a) =", id(a))
print("id(b) =", id(b))
a[0][0] = 0
print("a[0][0] = 0后，a =", a)
print("a[0][0] = 0后，b =", b)
a[0] = 1
print("a[0] = 1后，a =", a)
print("a[0] = 1后，b =", b)
def answer1():
"""
直接将列表a=列表b,那么a和b是完全相同的，a列表发生改变时，b列表会跟着改变
:return:
"""
print("输出一:")
a = [[1, 2], [3, 4]]
b = a
validate(a, b)
answer1()
def answer2():
"""
手动复制一层
:return:
"""
print("\n输出二:")
a = [[1, 2], [3, 4]]
b = []
for i in a:
b.append(i)
validate(a, b)
answer2()
def answer3():
"""
利用列表自带的copy方法，但是也只能copy一层
:return:
"""
print("\n输出三:")
a = [[1, 2], [3, 4]]
b = a.copy()
validate(a, b)
answer3()
def answer4():
"""
利用列表的切片
:return:
"""
print("\n输出四:")
a = [[1, 2], [3, 4]]
b = a[:]
validate(a, b)
answer4()
def answer5():
"""
深拷贝copy.deepcopy
:return:
"""
print("\n输出五:")
a = [[1, 2], [3, 4]]
b = copy.deepcopy(a)
validate(a, b)
answer5()
def answer6():
"""
浅拷贝copy.copy,同answer3
:return:
"""
print("\n输出六:")
a = [[1, 2], [3, 4]]
b = copy.copy(a)
validate(a, b)
answer6()
def answer7():
"""
使用列表生成式
利用列表的for处理，好像是生成器
:return:
"""
print("\n输出七:")
a = [[1, 2], [3, 4]]
b = [i for i in a]
validate(a, b)
answer7()
def answer8():
"""
利用列表乘以1来生成
序列相加 相乘：
[1,2,3]+[4,5,6]=[1,2,3,4,5,6] 学列相加就是连接在一起
[1,2,3]*3=[1,2,3,1,2,3,1,2,3] 序列乘以一个常数N就是将序列复制N次
[1,2,3]*[1,2,3]=[] 报错TypeError
:return:
"""
print("\n输出八:")
a = [[1, 2], [3, 4]]
b = a * 1
validate(a, b)
answer8()
def answer9():
"""
表1拓展到表2中
:return:
"""
print("\n输出九:")
a = [[1, 2], [3, 4]]
b = []
b.extend(a)
validate(a, b)
answer9()
