python3：str与bytes的相互转换

# bytes
orig_bytes = b"my is a bytes"
# str
orig_str = "my is a sting"

第一种方法：
# str转换为bytes
bytes(orig_str, encoding = 'utf-8') 
bytes(orig_str, 'utf-8')

# bytes转换为str
str(orig_bytes, encoding = 'utf-8')
str(orig_bytes, 'utf-8')

第二种方法:
# str转换为bytes
str.encode(orig_str)

# bytes转换为str
bytes.decode(orig_bytes)

In [2]: # bytes
   ...: orig_bytes = b"my is a bytes"
   ...: # str
   ...: orig_str = "my is a sting"

In [3]: '''第一种方法'''
   ...: # str转换为bytes
   ...: bytes(orig_str, encoding = 'utf-8')
Out[3]: b'my is a sting'

In [4]: # bytes转换为str
   ...: str(orig_bytes, encoding = 'utf-8')
Out[4]: 'my is a bytes'

In [5]: '''第二种方法'''
   ...: # str转换为bytes
   ...: str.encode(orig_str)
Out[5]: b'my is a sting'

In [6]: # bytes转换为str
   ...: bytes.decode(orig_bytes)
Out[6]: 'my is a bytes'