1樓：lxkaka
列舉一種場景，把資料寫入檔案再上傳到儲存服務比如阿里雲OSS， aws的S3，這個時候可以用ByetesIO來讀寫資料。
2樓：黃哥
Python 3 中字串是str型別，記憶體讀寫字串用StringIO。記憶體讀寫bytes 用BytesIO。bytes 和str 轉換用encode 和decode
In [4]: s = "黃哥"
In [5]: type(s)
Out[5]: str
In [6]: b = s.encode('utf-8')
In [7]: b
Out[7]: b'\xe9\xbb\x84\xe5\x93\xa5'
In [8]: type(b)
Out[8]: bytes
In [9]: c = b.decode('utf-8')
In [10]: c
Out[10]: '黃哥'
In [11]:
class io.StringIO(initial_value='', newline='\n')An in-memory stream for text I/O. The text buffer is discarded when the close() method is called.
The initial value of the buffer can be set by providing initial_value. If newline translation is enabled, newlines will be encoded as if by write(). The stream is positioned at the start of the buffer.
StringIO provides this method in addition to those from TextIOBase and its parents:
class io.BytesIO([initial_bytes])A stream implementation using an in-memory bytes buffer. It inherits BufferedIOBase.
The buffer is discarded when the close() method is called.
The optional argument initial_bytes is a bytes-like object that contains initial data.
BytesIO provides or overrides these methods in addition to those from BufferedIOBaseand IOBase:
getbuffer()16.2. io — Core tools for working with streams
Return a readable and writable view over the contents of the buffer without copying them. Also, mutating the view will transparently update the contents of the buffer:
>>>>>> b = io.BytesIO(b"abcdef")
>>> view = b.getbuffer()
>>> view[2:4] = b"56"
>>> b.getvalue()
b'ab56ef'
Note
As long as the view exists, the BytesIO object cannot be resized or closed.
New in version 3.2.
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