How to capitalise selected words in vim

https://stackoverflow.com/questions/17440659/capitalize-first-letter-of-each-word-in-a-selection-using-vim

:s/\<./\u&/g

• \< matches the start of a word
• . matches the first character of a word
• \u tells Vim to uppercase the following character in the substitution string (&)
• & means substitute whatever was matched on the left-hand side
• g means substitute all matches, not only the first

=======================================================

:help case says:

To turn one line into title caps, make every first letter of a word
uppercase:
    : s/\v<(.)(\w*)/\u\1\L\2/g

Explanation:

:                      # Enter ex command line mode.

space                  # The space after the colon means that there is no
                       # address range i.e. line,line or % for entire
                       # file.

s/pattern/result/g     # The overall search and replace command uses
                       # forward slashes.  The g means to apply the
                       # change to every thing on the line. If there
                       # g is missing, then change just the first match
                       # is changed.

The pattern portion has this meaning:

\v                     # Means to enter very magic mode.
<                      # Find the beginning of a word boundary.
(.)                    # The first () construct is a capture group.
                       # Inside the () a single ., dot, means match any
                       #  character.
(\w*)                  # The second () capture group contains \w*. This
                       # means find one or more word characters. \w* is
                       # shorthand for [a-zA-Z0-9_].

The result or replacement portion has this meaning:

\u                     # Means to uppercase the following character.
\1                     # Each () capture group is assigned a number
                       # from 1 to 9. \1 or back slash one says use what
                       # I captured in the first capture group.
\L                     # Means to lowercase all the following characters.
\2                     # Use the second capture group

Result:

ROPER STATE PARK
Roper State Park