>> line1: $string3 = "bacdeabcdefghijklabcdeabcdefghijkl";
>> line2: $string4 = "xxyyzzbatttvv";
>>
>> line3: print "\$1 = $1 [EMAIL PROTECTED],$+[0]}, \$& = $&\n"
>> if($string3
>> =~ /(a|b)*/);
>> line4: print "\$1 = $1 [EMAIL PROTECTED],$+[0]}, \$& = $&\n"
>> if($string4
>> =~ //);
>>
>> $1 = a @{0,2}, $& = ba
>> $1 = @{0,0}, $& =
>
>The regex says "match zero or more of (a or b)". In string 1, it
matches
>a 'b' and then an 'a' at the beginning, thus $& = 'ba'. In string 2,
it
>matches zero characters (because it's allowed to!) at the beginning,
thus
>$& eq ''.
yeah, I got the idea why $1 has value "a" in this condition, but other
question
still reamins:
If the regexp says "match zero or more of (a or b)", why can't we
match
an empty string in the first place? What causes "(a|b)*" to make no
difference
from "(a|b)+"?
Thanks!
Sincerely
Pine
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