python内存地址和编译字节码

查看内存地址

id() 函数用于获取对象的内存地址

a = '3'
b = '3'
print(id(a))
print(id(b))
>
140328813804208
140328813804208

结论： a和b指向相同的内存地址

编译后生成的字节码

dis.dis()函数可以查看编辑后的字节码

import dis

a = 'if a is not None: pass'
b = 'if not a is None: pass'

print(dis.dis(a))
print(dis.dis(b))

>
  1           0 LOAD_NAME                0 (a)
              2 LOAD_CONST               0 (None)
              4 COMPARE_OP               9 (is not)
              6 POP_JUMP_IF_FALSE        8
        >>    8 LOAD_CONST               0 (None)
             10 RETURN_VALUE
None
  1           0 LOAD_NAME                0 (a)
              2 LOAD_CONST               0 (None)
              4 COMPARE_OP               9 (is not)
              6 POP_JUMP_IF_FALSE        8
        >>    8 LOAD_CONST               0 (None)
             10 RETURN_VALUE
None

结论：a和b写法不同，但效果/性能均相同
```@[TOC](这里写自定义目录标题)