read_filter_lines: Read and Filter Matching Lines in Text Files

In seekr: Extract Matching Lines from Matching Files

Read and Filter Matching Lines in Text Files

Description

Reads lines from a set of text files and returns only the lines that match a specified regular expression pattern. The function processes each file one-by-one to maintain memory efficiency, making it suitable for reading large files. Files that cannot be read (due to warnings or errors) are skipped with a warning.

If verbosity is enabled via seekr.verbose = TRUE and the session is interactive, the function reports progress.

Usage

read_filter_lines(files, pattern, ...)

Arguments

files	A character vector of files to search (only for seek_in()).
pattern	A regular expression pattern used to match lines.
...	Additional arguments passed to readr::read_lines(), such as skip, n_max, or locale.

Details

Files are processed sequentially to minimize memory usage, especially when working with large files. Only the lines matching the pattern are retained for each file.

If a file raises a warning or an error during reading, it is silently skipped and contributes an empty entry to the result lists.

Value

A list with two elements:

line_number

A list of integer vectors giving the line numbers of matching lines, one per file.

line

A list of character vectors containing the matched lines, one per file.

seekr documentation built on Feb. 8, 2026, 9:06 a.m.