Cripes, I'd never realised that, thanks for pointing it out. I had to write a little piece of code to prove it to myself.

$ perl -le '
> $s1 = q{catDOGfish};
> $s2 = q{xxYYYzz};
> print $1 if $s1 =~ m{([A-Z]+)};
> print $1 if $s1 =~ m{([0-9]+)};
> print $1 if $s2 =~ m{};'
DOG
YYY
$
[download]

Fancy not knowing that after all this time!

Thanks again,

JohnGG