$1 in reg ex

Posted on 2002-05-20
Last Modified: 2010-03-05
What does this mean

$var =~ s/\D*(\d+)\D*/$1/;
Question by:castello
  • 2

Accepted Solution

bebonham earned 50 total points
ID: 7022159
it means

dasljda123123lkajslsjad  would become


it looks for a string that might have some stuff at the begenning or at the end or both and definitely has to have at least 1 number in it, and then it removes everything except for the number. and then the $var is just the number


Expert Comment

ID: 7022162
$1 is a reference to whatever is in side the first set of ()

Expert Comment

ID: 7022302
it's true that $1 is the string matched in the first use of the braces, but when using this within the regexp it's more elegent to use \1 instead.
LVL 84

Expert Comment

ID: 7023280
Since it's not used within the regexp here, $1 is correct in the substitution

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