Linefrom

Linefrom is a descriptive term used in programming and text processing for a utility or function that retrieves a single line from a text source, identified by its line number or by a specific criterion. It is not a standardized function across all languages, but many libraries and projects implement a similar concept under various names.

Common behavior and variations

Linefrom typically takes a source (such as a string, a list of lines, or a file) and an index indicating which line to return. Indexing may be one-based or zero-based, and behavior when the requested line is out of range varies: some implementations return a null or undefined value, others raise an error or return an empty string. Some variants allow additional criteria, such as returning the next line that matches a pattern after a given offset.

Implementation approaches

When operating on in-memory text, linefrom can be implemented by splitting the source into lines and selecting the nth element. For example, in pseudocode: linefrom(source, n) = lines(source)[n-1] (one-based indexing). For large files or streams, a streaming approach is preferred to avoid loading the entire content into memory, typically iterating through lines until the target is reached. Languages may expose built-in primitives such as readline or similar utilities, and some may offer direct random access for certain file formats.

Applications and context

Linefrom is commonly used in log analysis, data processing pipelines, text editors, and scripting tasks that require precise line access. It emphasizes simplicity and direct retrieval of a specific line, as opposed to parsing or filtering broader sections of text.

See also

getLine, readline, nth line, readlines.