Hi Monks,

I played with regular expression and perl does something different as I would expect. Only the "+" operator worked as expected. When the "*" or "?" is at the end of a expression, is seems it is sometimes not greedy. Please see my example: 

use strict;
use warnings;

$_="kkkaaabc"; 
print "String = $_\n";
print "1 $&      Expected: ka     ?? /k?a?/\n" if /k?a?/;
print "2 $&   Expected: kkka   OK\n"    if /k*a?/;
print "3 $&   Expected: kaaa   OK\n"    if /k?a+/;
print "4 $& Expected: kkkaaa OK\n"      if /k+a+/;
print "5 $&      Expected: kaaa   ?? /k?a*/\n" if /k?a*/;
print "6 $& Expected: kkkaaa OK\n"      if /k*a*/;

[download]

The result is: 

String = kkkaaabc
1 k      Expected: ka     ?? /k?a?/
2 kkka   Expected: kkka   OK
3 kaaa   Expected: kaaa   OK
4 kkkaaa Expected: kkkaaa OK
5 k      Expected: kaaa   ?? /k?a*/
6 kkkaaa Expected: kkkaaa OK

[download]

Why do I get in case 1 and 5 no "a" at the end of the matching circuit ??. Many Thanks for any help !

In reply to basic question: regular expression by Anonymous Monk

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