Filter buffer on a search result

Tip 1557 Printable Monobook Previous Next

created April 22, 2008 · complexity basic · author Niels AdB · version 7.0

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You may want to list all lines in the current buffer that match a pattern, for example, list all lines containing "Warning". The following script copies all matching lines to a scratch (temporary) buffer. You can then examine the list, or save it to a file.

Create a file called (for example) filter.vim containing:

" Gather search hits, and display in a new scratch buffer.
function! Gather(pattern)
  if !empty(a:pattern)
    let save_cursor = getpos(".")
    let orig_ft = &ft
    " append search hits to results list
    let results = []
    execute "g/" . a:pattern . "/call add(results, getline('.'))"
    call setpos('.', save_cursor)
    if !empty(results)
      " put list in new scratch buffer
      new
      setlocal buftype=nofile bufhidden=hide noswapfile
      execute "setlocal filetype=".orig_ft
      call append(1, results)
      1d  " delete initial blank line
    endif
  endif
endfunction

" Delete the current buffer if it is a scratch buffer (any changes are lost).
function! CloseScratch()
  if &buftype == "nofile" && &bufhidden == "hide" && !&swapfile
    " this is a scratch buffer
    bdelete
    return 1
  endif
  return 0
endfunction

nnoremap <silent> <Leader>f :call Gather(input("Search for: "))<CR>
nnoremap <silent> <Leader>F :call Gather(@/)<CR>
nnoremap <silent> <Esc> :call CloseScratch()<CR>

In Vim, the command :source filter.vim will execute the script.

Assuming the default leader key (backslash), you can now:

• Type \f and enter a pattern when prompted.
• Type \F to filter on the last search pattern.
• Press Escape to close the scratch buffer listing the search hits.

For example, you could put the cursor on a word and press * to search for the next occurrence of that word. If you now type \F a new window will open with a list of all lines that contain the word you searched for. Press Escape to close the window.

Alternative procedures

A simple procedure to list all lines matching a pattern is:

" Print all lines that contain "pattern".
:g/pattern/p
" Following is equivalent.
:g/pattern

The following will delete all lines that do not contain a pattern, leaving only the search hits. You could then press u to undo the changes.

:v/pattern/d

See also

• Folding with Regular Expression to fold away lines without a search pattern rather than modifying it or using a scratch buffer
• Search for lines not containing pattern for some simple techniques to display lines of interest
• Copy the search results into clipboard to copy matching patterns (not lines)
• Send output of g search to a new window uses :redir with g//p for a limited one-line version of this tip
• List lines with current search pattern highlighted defines command PP to highlight matches displayed with :g//PP