Reverse a word in Vim

Question

How can I reverse a word in Vim? Preferably with a regex or normal-mode commands, but other methods are welcome too:

word => drow

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Answer 1

Here is another (pythonic) solution based on how this works:

:echo join(reverse(split('hello', '.\zs')), '')
olleh

If you want to replace all words in the buffer,

:%s/\(\<.\{-}\>\)/\=join(reverse(split(submatch(1), '.\zs')), '')/g

This works by first creating a list of characters in the word, which is reversed and joined back to form the word. The substitute command finds each word and then passes the word to the expressions and uses the result as replacement.