2018-08-19

2018-08-19  本文已影响0人  白s圣诞节

一、==和is的区别:

*==

比较两个对象是否相等

a = [11,22,33]
b = a
a == b
True
a = 23
b = a 
a == b
True
a = [11,22,33]
b = [11,22,33]
a == b
True
a = 24
b = 24
a == b
True

*is

比较两个引用是否指向了同一个对象(引用比较)(大于256就是false)

a = 180
b = 180
a is b
True
a = 257
b = 257
a is b
False
a = 257
b = a
a is b
True
a = 180
b = a
a is b
True
a = [11,22]
b = [11,22]
a is b
False
a = [11,22]
b = a
a is b
True

二、深拷贝、浅拷贝

*浅拷贝:(拷贝了引用,并没有拷贝内容)

image.png
image.png

*深拷贝:(对于一个对象所有层次的拷贝)

image.png
image.png
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