Meaning
Moves the file pointer to a given offset from a reference point (whence) for subsequent read/write operations.
Primary Function
Change the current file position of a file-like object.
Communicative Purpose
Instruct the file object to reposition its internal cursor so that the next I/O operation occurs at the desired location.
Pattern
file.seek(offset, whence)
Core Structure
file.seek(..., ...)
Função primária
Change the current file position of a file-like object.
Propósito comunicativo
Instruct the file object to reposition its internal cursor so that the next I/O operation occurs at the desired location.
Situações de gatilho
When needing to read/write at a specific byte offset, skip bytes, rewind to the start, or append at the end of a file.
Contextos
File I/O operations in binary or text mode; random-access file processing; implementing custom streams or buffers.
Padrão
file.seek(offset, whence)
Estrutura central
file.seek(..., ...)
Slots de substituição
offset (int), whence (int: 0=os.SEEK_SET, 1=os.SEEK_CUR, 2=os.SEEK_END)
Colocados típicos
- open
- read
- write
- tell
- os.SEEK_SET
- os.SEEK_CUR
- os.SEEK_END
Substituições comuns
- whence: os.SEEK_SET
- os.SEEK_CUR
- os.SEEK_END
- offset: any integer (positive
- zero
- or negative where allowed)
Erros comuns
Using invalid whence values (not 0,1,2); using negative offset with SEEK_SET; seeking in text mode with arbitrary offsets (only offsets from tell() are safe); confusing seek() with tell().
Similar / contraste
tell() (returns current position) vs seek() (sets position); truncate() (changes file size) vs seek() (only moves pointer).
Interferências
Confusing seek with tell; seeking in text mode may raise IOError unless offset comes from tell(); mixing text and binary modes can lead to unexpected positions.
Família do chunk
- file_io
Nuance
In text mode, seeking is only reliable to positions obtained from tell(); arbitrary offsets may fail due to encoding nuances. In binary mode, any integer offset is allowed.
Efeito pragmático
Signals the intention to perform random-access read/write by repositioning the file pointer before the next I/O operation.
Dica de memória
Think of seeking like moving a bookmark to a specific page in a book before reading or writing.
Nota
The whence parameter defaults to os.SEEK_SET (0) if omitted; os.SEEK_SET, os.SEEK_CUR, os.SEEK_END are constants from the os module.
Upgrade path
Learn tell(), truncate(), and the differences between text and binary modes for seeking.
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