How to replace only within visual selection?

Question

How does one get vim to replace a character within the visual selection only and not elsewhere on the line? Example:

• Line: int arr[] = { 00 01 02 03 04 05 05 /* ... lots more like this*/};
• Visual Selection: { 00 01 02 03 04 05 05 /*... lots more like this*/}
• Command: :'<,'>s/\ /\,0x/g
• Expected: int arr[] = {0x00,0x01,0x02,0x03 /* and so on*/};

After performing these actions however, the actual result is:

int,0xarr[],0x=,0x{0x00,0x01,0x02,0x03 /* and so on*/};

Is there a way to modify the command above to produce the expected result? Doesn't '< and '> define the range on which the search (and replace) commands work?

Answer 1

:'<,'>s/\%V\ /\,0x/g

%V matches inside the visual area. See :help %V.

Answer 2

There’s \%V for that, see :h %V:

%V

Match inside the Visual area. When Visual mode has already been stopped match in the area that gv would reselect. This is a /zero-width match. To make sure the whole pattern is inside the Visual area put it at the start and end of the pattern, e.g.: > /%Vfoo.*bar%V

To replace foo by bar in the selection only, use:

:'<,'>s/\%Vfoo\%V/bar/
:'<,'>s/\%Vfoo\%V/bar/g
:'<,'>s/\%Vfoo\%V/bar/cg

In this particular case:

:'<,'>s/\%V\ \%V/\,0x/g

Answer 3

If you want to substitute within a visual block, you can use the vis.vim plugin.

http://vim.wikia.com/wiki/Applying_substitutes_to_a_visual_block

To install:

Download vis.vba.gz from http://www.drchip.org/astronaut/vim/index.html#VIS

# Open vis.vba.gz in Vim 7.1 or later.
vim vis.vba.gz

# Source the open file.
:so %

# Quit Vim
:q

Once installed:

ctrl-v to enter visual-block mode
Move to select the block you want
:B s/pattern/newtext/

When you type :B, you will see this

:'<,'>B 

That's fine, it's just vim saying that the command will apply to the currently selected visual block.

Even better, you can perform any Ex command on the visual block, not just substitutions. For example :B !sort.

Answer 4

Set vnoremap :s :s/\%V\%V/<Left><Left><Left><Left>.

It adds \%V guards and places cursor in the middle. Use End or Ctrl+E to enter replacement pattern.

Answer 5

Following @dessert, I found the description and example a little confusing until I recognized %V wraps pattern.

:'<,'>s/pattern/newtext/

Becomes,

:'<,'> s/ \%V foo \%V / bar /

Remove the spaces,

:'<,'>s/\%Vfoo\%V/bar/gc

(because I always regret not using g-lobal, c-onfirmation)