Question

I frequently must correct the following rails code:

assert_equal value, expected 

The two arguments to assert_equal are out of order, and should read:

assert_equal expected, value 

In vim, what is the most efficient way of going from the first line to the second?

Answer 1

Via regex:

:s/\v([^, ]+)(\s*,\s*)([^, ]+)/\3\2\1/ 

If you do it often you can make a map out of it, e.g.:

:nmap <F5> :s/\v([^, ]+)(\s*,\s*)([^, ]+)/\3\2\1/<CR> 

Put the cursor on the line you want to flip and hit F5.