Hello,
Hello,
I am building a primary key for a database, and I guess the first question would be how safe is a key made from the last 4 digits of a social security num and the first 3 letters of the last name.
Do you mean safe as in unique? Or do you mean safe because you are using a social security number which may be illegal in some places and could expose your customers to identity theft?
Now for the PERL question, I have substr. line working correctly.
I wanted to try it with ReGrex, but the syntax is escaping me. Any pointers would appreciated!
#!/usr/bin/perl -w #use strict;
$ss = '1234567890'; $lname = 'Gilden'; # $pkey = substr($ss,length($ss)-4,length($ss)) . substr($lname,0,3);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
A verbose way of writing:
substr($ss,-4)# print "$pkey\n";
$ss = '09876543';
$lname = 'Smith';
# this line is bad! -- trying to have the same functionality as the substr line.
$pkey = ($ss =~ m/\d{length($ss)-4}($ss{length($ss)})/);
# $pkey = ($pkey =~ m/$lname{0,3}/;) print "$pkey\n";
If you want to do the same thing with the match operator:
my $ss = '09876543'; my $lname = 'Smith';
( $ss ) = $ss =~ /(.{4})$/;
( $lname ) = $lname =~ /^(.{3})/;my $pkey = "$ss$lname";
Or using the substitution operator:
my $ss = '09876543'; my $lname = 'Smith';
$ss =~ s/.*(.{4})$/$1/;
$lname =~ s/^(.{3}).*/$1/;my $pkey = "$ss$lname";
# Is there any advantage using =~ m/(\w){3}/ over substr method?
Not really. Of course you could use pack or unpack or sprintf instead. :-)
John -- use Perl; program fulfillment
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