How do I delete, change, or yank an entire sentence as a text object in Vim?

Explanation

Vim defines a sentence as text ending with ., !, or ? followed by whitespace or a newline. The as (around sentence) and is (inner sentence) text objects let you operate on complete sentences in one motion — no need to manually select from the start of a capital letter to the trailing period.

How it works

• as selects the sentence and the trailing whitespace (or leading whitespace if at end of paragraph).
• is selects the sentence text only, without surrounding whitespace.
• Combine with any operator: d (delete), c (change), y (yank), v (visual select), gU (uppercase), etc.

Example

Given the text:

The quick brown fox. It jumps over the lazy dog. Then it runs away.

With the cursor anywhere on It jumps over the lazy dog.:

• das → deletes the sentence including one space: The quick brown fox. Then it runs away.
• dis → deletes only the sentence text, leaving the space: The quick brown fox. Then it runs away.
• cas → deletes and enters insert mode to type a replacement sentence.

Tips

• ( and ) navigate between sentence boundaries without selecting them.
• Sentences must end with ., !, or ? followed by two spaces, a tab, or a newline for Vim to recognise them. A single space after a period (common in modern writing) may not be recognised — adjust with :set nrformats has no effect here; instead consider using a visual selection.
• Works in visual mode too: vas to enter visual mode selecting the sentence.
• Use 3das (or d3as) to delete three consecutive sentences at once.