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Filter knitr output by line indices

set_filter_output.Rd

Sets a custom knitr output hook that filters printed output, keeping only the lines specified in the chunk option lines. This is useful when you want to show only selected parts of console output in knitted documents.

Usage

set_filter_output()

Value

Invisibly returns NULL. Called for its side effects.

Details

The function modifies knitr's global output hook. Call it once (e.g., in a setup chunk) to activate the behavior for the rest of the document.

The hook:

  • splits the output into lines using xfun::split_lines()

  • selects lines via an internal helper filor:::.grep_lines()

  • passes the filtered output to the original knitr output hook

See also

knit_hooks

Examples

if (FALSE) { # \dontrun{
set_filter_output()

## In an R Markdown chunk:
## ```{r, lines = c(1, 3, 5)}
## print(1:10)
## ```
} # }