Python中有六大数据类型:数字(int, float等),字符串str,列表list,字典dict,集合set,元组tuple
其中
可变类型有:列表list,字典dict,集合set
不可变类型有:数字(int, float等),字符串str,元组tuple
目录
一、对于可变类型
1,引用:=赋值符号
a = {"a": 1, "b": 2}
b = a
print(a) # {'a': 1, 'b': 2}
print(b) # {'a': 1, 'b': 2}
print(id(a)) # 3231591188544
print(id(b)) # 3231591188544
print(a == b) # True
print(a is b) # True
使用赋值引用=符号时不会拷贝(不会开辟新地址)
2,浅拷贝:copy.copy()方法
import copy
a = {"a": 1, "b": 2}
b = copy.copy(a)
print(a) # {'a': 1, 'b': 2}
print(b) # {'a': 1, 'b': 2}
print(id(a)) # 3159722903616
print(id(b)) # 3159722903680
print(a == b) # True
print(a is b) # False
对于可变类型,无论是深浅拷贝都会拷贝(开辟新地址)
3,深拷贝:copy.deepcopy()方法
import copy
a = {"a": 1, "b": 2}
b = copy.deepcopy(a)
print(a) # {'a': 1, 'b': 2}
print(b) # {'a': 1, 'b': 2}
print(id(a)) # 2130634229824
print(id(b)) # 2130636795264
print(a == b) # True
print(a is b) # False
对于可变类型,无论是深浅拷贝都会拷贝(开辟新地址)
二、对于不可变对象
1,引用:=赋值符号
import copy
x = (1, 2)
y = x
print(x) # (1, 2)
print(y) # (1, 2)
print(id(x)) # 2722753740672
print(id(y)) # 2722753740672
print(x == y) # True
print(x is y) # True
使用赋值引用=符号不会拷贝(不会开辟地址)
2,浅拷贝:copy.copy()方法
import copy
x = (1, 2)
y = copy.copy(x)
print(x) # (1, 2)
print(y) # (1, 2)
print(id(x)) # 2464879148928
print(id(y)) # 2464879148928
print(x == y) # True
print(x is y) # True
对于不可变类型,无论是深浅拷贝都不会拷贝(不会开辟新地址)
3,深拷贝:copy.deepcopy()方法
import copy
x = (1, 2)
y = copy.copy(x)
print(x) # (1, 2)
print(y) # (1, 2)
print(id(x)) # 2464879148928
print(id(y)) # 2464879148928
print(x == y) # True
print(x is y) # True
对于不可变类型,无论是深浅拷贝都不会拷贝(不会开辟新地址)
三、对于可变复合对象
1,引用:=赋值符号
import copy
z = [1, {"age": 33}, (11, 22)]
w = z
print(z) # [1, {'age': 33}, (11, 22)]
print(w) # [1, {'age': 33}, (11, 22)]
print(id(z)) # 2254907732608
print(id(w)) # 2254907732608
print(z == w) # True
print(z is w) # True
print(z[0] is w[0]) # True
print(z[1] is w[1]) # True
print(z[2] is w[2]) # True
对于可变复合对象:使用赋值引用=符号时都不会拷贝(不会开辟新地址)
2,浅拷贝:copy.copy()方法
import copy
z = [1, {"age": 33}, (11, 22)]
w = copy.copy(z)
print(z) # [1, {'age': 33}, (11, 22)]
print(w) # [1, {'age': 33}, (11, 22)]
print(id(z)) # 1276900438976
print(id(w)) # 1276900113088
print(z == w) # True
print(z is w) # False
print(z[0] is w[0]) # True
print(z[1] is w[1]) # True
print(z[2] is w[2]) # True
对于可变复合对象:使用浅拷贝时只会拷贝(开辟新地址)第一层数据(最外层数据),里面所有嵌套的数据无论是否是可变类型都不会拷贝(不会开辟新地址)
3,深拷贝:copy.deepcopy()方法
import copy
z = [1, {"age": 33}, (11, 22)]
w = copy.deepcopy(z)
print(z) # [1, {'age': 33}, (11, 22)]
print(w) # [1, {'age': 33}, (11, 22)]
print(id(z)) # 2109476139456
print(id(w)) # 2109468071872
print(z == w) # True
print(z is w) # False
print(z[0] is w[0]) # True
print(z[1] is w[1]) # False
print(z[2] is w[2]) # True
对于可变复合对象:使用深拷贝时会根据数据是否是可变类型进行拷贝,是可变类型就拷贝(开辟新地址),不可变类型不拷贝(不开辟新地址)
四、对于不可变复合对象
1,引用:=赋值符号
import copy
tuple1 = (1, {"age", 10}, "abc", [11, 22, 33])
tuple2 = tuple1
print(tuple1) # (1, {10, 'age'}, 'abc', [11, 22, 33])
print(tuple2) # (1, {10, 'age'}, 'abc', [11, 22, 33])
print(id(tuple1)) # 2307305972576
print(id(tuple2)) # 2307305972576
print(tuple1 == tuple2) # True
print(tuple1 is tuple2) # True
print(tuple1[0] is tuple2[0]) # True
print(tuple1[1] is tuple2[1]) # True
print(tuple1[2] is tuple2[2]) # True
print(tuple1[3] is tuple2[3]) # True
对于不可变复合对象:使用赋值引用=符号时都不会拷贝(不会开辟新地址)
2,浅拷贝:copy.copy()方法
import copy
tuple1 = (1, {"age", 10}, "abc", [11, 22, 33])
tuple2 = copy.copy(tuple1)
print(tuple1) # (1, {10, 'age'}, 'abc', [11, 22, 33])
print(tuple2) # (1, {10, 'age'}, 'abc', [11, 22, 33])
print(id(tuple1)) # 2523963556384
print(id(tuple2)) # 2523963556384
print(tuple1 == tuple2) # True
print(tuple1 is tuple2) # True
print(tuple1[0] is tuple2[0]) # True
print(tuple1[1] is tuple2[1]) # True
print(tuple1[2] is tuple2[2]) # True
print(tuple1[3] is tuple2[3]) # True
对于不可变复合对象:使用浅拷贝时都不会拷贝(不会开辟新地址)
3,深拷贝:copy.deepcopy()方法
import copy
tuple1 = (1, {"age", 10}, "abc", [11, 22, 33])
tuple2 = copy.deepcopy(tuple1)
print(tuple1) # (1, {10, 'age'}, 'abc', [11, 22, 33])
print(tuple2) # (1, {10, 'age'}, 'abc', [11, 22, 33])
print(id(tuple1)) # 1417646908096
print(id(tuple2)) # 1417655276304
print(tuple1 == tuple2) # True
print(tuple1 is tuple2) # False
print(tuple1[0] is tuple2[0]) # True
print(tuple1[1] is tuple2[1]) # False
print(tuple1[2] is tuple2[2]) # True
print(tuple1[3] is tuple2[3]) # False
对于不可变复合对象:使用深拷贝时会根据数据是否是可变类型进行拷贝,是可变类型就拷贝(开辟新地址),不可变类型不拷贝(不开辟新地址)
结论:
对于可变类型,无论是深浅拷贝都会开辟新地址,使用赋值引用=符号时不会开辟新地址 对于不可变类型,无论是深浅拷贝都不会开辟新地址,使用赋值引用=符号也不会开辟地址
对于可变复合对象:使用浅拷贝时只会拷贝(开辟新地址)第一层数据(最外层数据),里面所有嵌套的数据无论是否是可变类型都不会拷贝(不会开辟新地址) 对于可变复合对象:使用深拷贝时会根据数据是否是可变类型进行拷贝,是可变类型就拷贝(开辟新地址),不可变类型不拷贝(不开辟新地址)
对于不可变复合对象:使用浅拷贝时都不会拷贝(不会开辟新地址) 对于不可变复合对象:使用深拷贝时会根据数据是否是可变类型进行拷贝,是可变类型就拷贝(开辟新地址),不可变类型不拷贝(不开辟新地址)
对于可变和不可变复合对象:使用赋值引用=符号时都不会拷贝(不会开辟新地址)