From: Warren Brown <warrenb@...>
Date: 2005-04-06T23:58:15+09:00
Subject: Re: Regular expression mismatch ?

Han,

> Why does the following:
>
> s = "aaa aaa\n\n\nbbb bbb"
> puts(s =~ /^\s+$/)
>
> produce: 8  (instead of nil) ?

    Because /^/ matches the beginning of a line (not the beginning of
the string), and /\s/ matches whitespace, which includes newlines (\n).
So the first place in the string where the beginning of a line is
followed by one or more whitespaces is at position 8.

> (If I put in only 2 newlines, it's fine).

    With only two newlines, the /$/ prevents the match, since there are
"b"s following the newline.

    I hope this helps.

    - Warren Brown