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what below code do

abcdef
New User

Feb 9, 2011, 10:31 PM

Post #1 of 2 (1483 views)

what below code do	Can't Post

Hi,

I have below code :

my($abc) = "fred<hello>3hello";
$abc =~ /^[^\d]{2,4}<([^>]+)>\d?\1$/;

if (defined($1)) {
print "$1\n";
} else {
print "not found\n";

}
}

What is the code doing ?? what function of the regular expression

$abc =~ /^[^\d]{2,4}<([^>]+)>\d?\1$/;

??

budman
User

Feb 10, 2011, 3:26 PM

Post #2 of 2 (1470 views)

Re: [abcdef] what below code do [In reply to]	Can't Post

In Reply To

What is the code doing ?? what function of the regular expression

$abc =~ /^[^\d]{2,4}<([^>]+)>\d?\1$/;

??

Code

  /^                       start of line 
   [^\d]{2,4}      match any non-digit (chars)  
                                containing between 2 and 4 letters 
   <([^>]+)>      inside the angle brackets  store the 
                               contents in $1 upto the first  
                               right angle bracket 
   \d?\1               then check for one digit and 
                               look-ahead (?) for the text we stored 
                               in $1 (\1 is a reference to $1) 
  $/                       with nothing else til the end of the line

Works for
"fr<hello>3hello"
"fre<hello>3hello"
"fred<hello>3hello"

Then prints 'hello' in the case.

"xx<testing>9testing"
"xxx<testing>9testing"
"xxxx<testing>9testing"

These will also work, and print 'testing'

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