file.detach() Detach raw stream
Last updated: 2026-09-22
file.detach() Detach raw stream
file.detach() separates the underlying binary buffer from the text stream.
| Category | File Methods |
|---|---|
| Kind | Built-in Type Method |
| Python Version | all |
📝 Syntax
file.detach()Returns：The separated underlying binary stream (e.g. FileIO); the text stream becomes unusable.
Mutates the original：No (returns a new object)
💥 Raises
ValueError— Raised when the stream is already detached or the raw stream has been used.UnsupportedOperation— Raised when the stream does not support detaching.
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
FileIO💡 Related Cases
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❓ FAQ
QWhat does detach() do?
AIt separates and returns the underlying binary buffer of the text stream; after detaching, the text stream can no longer be used, and further operations raise ValueError.
QWhen should it be used?
AWhen you need direct operations on the underlying binary object; in normal cases it is not needed, and for everyday reading/writing the with statement is enough.
QIn which cases does it raise an exception?
AWhen the stream is already detached, or the underlying stream has already been used (such as read/write), it raises ValueError; streams that do not support detaching raise UnsupportedOperation.
