Regular Expression to match only one angle bracket

Question

I\'m looking for a regular expression that matches the \'>\' in

a > b
>
b>
...

but not two or more angled brackets, i.e. it should

Answer 1

perreal's first regex is correct. However, the second regex given in that answer subtly fails in one condition. Since it captures characters both before and after, two >s separated by a single character will not both be found.

Here is a regex which only uses forward lookaheads and doesn't have that problem:

(?:^|[^>])(>)(?:$|(?!>))

Edit live on Debuggex

Answer 2

Perl syntax:

/(?<!>)>(?!>)/

Without using lookahead or lookbehind:

/(?:^|[^>])>(?:[^>]|$)/

Answer 3

The issue here is that when you use the lookahead, you're matching the second > (there's no > after the second >), and when you're using the lookbehind, you're matching the first >.

You could probably use this:

[^>]>[^>]

There's a >, with no > before or after it.

But I think that to suit what you exactly need, need to use lookaheads and lookbehinds both:

(?<!>)>(?!>)