How to perform arithmetic manipulations on numbers in Vim?

Question

If I have a data file with columns of numbers like

3.14 0.42 6.66 

Is there a way from within Vim to manipulate these with operations such as addition, subtraction, and division? For instance, say I want to add 2.1 to each number in a column, how should I go about this?

I can do it by piping to, for instance, an Awk script, but I would like to know if there is a builtin method, and I haven’t found anything in the help files.

Answer 1

Use CTRL-R with the expression register =.

The following command would add 2.1 to a number on a line:

C <CTRL-R> = <CTRL-R> " +2.1 <ENTER> 

Combine with macro it can yield some interesting results, such as this example.

Answer 2

Expression registers are great with vim.

Here is a more old fashioned vi way to doing this: Let us say you have a file containing a bunch of numbers one in each line and you want to add 2.1 to each of the lines.

:%s/$/+2.1/<ENTER> - this would append +2.1 to each line. :1<ENTER>  - Goto the beginning of the file  !Gbc<ENTER> - invoke the bc command on each line to do the addition.