Re: Understanding alternation

[g0n]

'Does the match quit once it finds the first occurence of one of the alternatives?'

Yes.

'Will that then try and match each alternative in the string and then return?'

Sort of. It will keep looking through the string, even after it's found a match, until it doesn't find any more matches. It's a fine distinction, but it doesn't look through the string for the first, then look through again for the second etc, AFAIK. Note that in the context you are using it, it will just return true, not a list of matches.

'Can I do that using the alternation ..'

Yes, like this:

$text = "The dog is black cat is white and the fox does not like the c
+ow or pig";
$text =~ s/(dog|cow|cat|pig)/\n$1/g;
print $text;

($1 contains the value matched by the pattern, so you are replacing each match with itself, prepended by \n).

[McDarren]

I'd throw a couple of \b's in there, so it only matches on word boundaries. eg:

$text =~ s/\b(dog|cat|fox|cow|pig)\b/\n$1/g;

Otherwise, you'd match stuff like "cowardly" and "pigheaded" ;)

[Anonymous Monk]

Ok seems fairly straightforward thanks for the help