Tip #205: Computing a sum of numbers in vim

created:		January 30, 2002 3:05		complexity:		advanced
author:		Stanislav Sitar		as of Vim:		6.0

"Sometimes you need to sum a some numbers in vim.  There *are* some plugins
"that can do the job.  But what if the numbers are not in a columns or are on
"the same line or are sacttered all across the file? You might also need to
"sum all the numbers in file that look like '1234$', or '54565 Eu'  ignoring others.
"
"There is a very simple trick, using (my favourite) command
":s
"
"First you define following function

:let g:S=0 "In global variable S we later find the result

:function! Sum(number) "The function is defined with a '!',
"so it does not complain during debugging
"when you are redefining the function
:let g:S=g:S+a:number "we accumulate the result in global variable S
:return a:number "function returns the argument, so after a :s
"command the text remains the same
:endfunction

"you can do issue those few commands from a command line,
"or create a small file and put it into your plugin directory,
"or write those few commands into a file end issue a command :so %



"how to use this little function:
"let's suppose you have a simple column of numbers like
"
"10
"20
"30
"
"you issue command like:
:let S=0
:%s/[0-9]\+/\=Sum(submatch(0))/
"the command finds the first number on the line and adds it to the S
"
"the result is displayed
:echo $S

"!!!! don't forget to do
:let g:S=0
"before use.

"you can also use \zs and \ze atoms in a regular expression to
"delimit the number, so submatch(0) returns only a number and
"the text remains unchanged after 'substitute'


"for starter on the wonderfull world of regular expressions see:
:help usr_27.txt

"for the definition of the search pattern see
:help :s
:help pattern

"for replacement strings begining with \= and special function submatch(0)see
:help sub-replace-special

"for the *ultimate* guide through the world of regular expressions see book:
"Mastering Regular Expressions
"Powerful Techniques for Perl and Other Tools
"by Jeffrey E.F. Friedl
"from O'REILLY

"the book does not write about vim, yet here you can learn that
":s command is the most powerfull command you can find in a text editor.
"(with the possible exception of :global command)


<< Some mappings for using cscope with vim. | Highlight doubled word errors in text >>

Additional Notes