Looping

You might be surprised to realize that we've gone through thirty five chapters of a programming language book without even mentioning loops! Vimscript offers so many other options for performing actions on text (normal!, etc) that loops aren't as necessary as they are in most other languages.

Even so, you'll definitely need them some day, so now we'll take a look at the two main kinds of loops Vim supports.

For Loops

The first kind of loop is the for loop. This may seem odd if you're used to Java, C or Javascript for loops, but turns out to be quite elegant. Run the following commands:

:let c = 0

:for i in [1, 2, 3, 4]
:  let c += i
:endfor

:echom c

Vim displays 10, which is the result of adding together each element in the list. Vimscript for loops iterate over lists (or dictionaries, which we'll cover later).

There's no equivalent to the C-style for (int i = 0; i < foo; i++) loop form in Vimscript. This might seem bad at first, but in practice you'll never miss it.

While Loops

Vim also supports the classic while loop. Run the following commands:

:let c = 1
:let total = 0

:while c <= 4
:  let total += c
:  let c += 1
:endwhile

:echom total

Once again Vim displays 10. This loop should be familiar to just about anyone who's programmed before, so we won't spend any time on it. You won't use it very often. Keep it in the back of your mind for the rare occasions that you want it.

Exercises

Read :help for.

Read :help while.