Meaning
Opens a file and immediately closes it, releasing the file handle back to the operating system. Addresses the risk of file descriptor leaks when performing brief file operations such as metadata checks. Reached for when you need to touch a file momentarily without reading or writing substantial data.
Primary Function
File handling
Communicative Purpose
Ensures a file is opened and then closed to release system resources after a short operation.
Pattern
open(resource, mode).close()
Core Structure
open(...).close()
Função primária
File handling
Propósito comunicativo
Ensures a file is opened and then closed to release system resources after a short operation.
Situações de gatilho
File utilities: checking file metadata like size without reading content; System scripts: creating or touching a file to confirm accessibility; Low-level I/O: briefly acquiring a file handle and releasing it quickly
Contextos
Scripts that process binary files, low-level file utilities, data pipelines that handle raw bytes.
Padrão
open(resource, mode).close()
Estrutura central
open(...).close()
Slots de substituição
resource: str or path-like object representing the file path; mode: str indicating file mode (e.g., 'r', 'w', 'rb', 'wb')
Colocados típicos
- os.path.getsize
- os.fstat
- struct.unpack
- file.read
- file.write
Substituições comuns
- Using a with statement (context manager) for automatic closing
- using pathlib.Path.open()
- using os.open and os.close for lower-level descriptors.
Erros comuns
Failing to close the file handle if an exception occurs between open and close; opening the file in the wrong mode (e.g., text mode for binary data); assuming the file exists without handling FileNotFoundError.
Similar / contraste
Using `with open(...) as f:` ensures the file is closed even if an exception occurs; using `open(...).read()` without explicit close relies on garbage collection; using `os.open` returns a file descriptor requiring `os.close`.
Interferências
Coming from Java or C#: developers may rely on garbage collection to close files and forget to call close() explicitly → Python's GC is non-deterministic, so explicit close() or a context manager is required. Coming from C: may expect open/close to return error codes → Python raises exceptions on failure rather than returning status values.
Família do chunk
- file handling
- resource management
- context manager pattern
Nuance
If an exception is raised after open but before close, the file remains open, causing a resource leak; better to use a context manager; opening very large files just to check metadata is inefficient; consider using os.path.getsize or pathlib.Path.stat instead.
Efeito pragmático
Guarantees that the file descriptor is released, preventing OS-level resource leaks and allowing other processes to access the file.
Dica de memória
Open the door, do your business, then close it.
Nota
This pattern is considered low-level; in modern Python code prefer the `with` statement for automatic resource management.
Upgrade path
Replace with `with open(resource, mode) as f:` block.
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