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regex/substitution on multiple cases

joseph4325
Novice

Jul 15, 2013, 9:49 AM

Post #1 of 6 (2088 views)

regex/substitution on multiple cases	Can't Post

my $names = "Bill and Steve and Jeff"

The goal is to do a substitution on this line that does the following:
1. s/Bill/Bob/ and s/Jeff/Jim/
2. substitute any character that does not match "Bill" or "Jeff" and replace with nothing.

Desired output: "BobJim"

I can do the first part, but not the 2nd.

Laurent_R
Veteran / Moderator

Jul 15, 2013, 10:39 AM

Post #2 of 6 (2085 views)

Re: [joseph4325] regex/substitution on multiple cases [In reply to]	Can't Post

One of many ways to do it (under the Perl debugger):

Code

  DB<36> $names = "Bill and Steve and Jeff" 
 
  DB<37> $names =~ s/Bill/Bob/ 
 
  DB<38> $names =~ s/Jeff/Jim/ 
 
  DB<39> p $names 
Bob and Steve and Jim 
  DB<40> $names =~ s/(Bob).*(Jim)/$1$2/ 
 
  DB<41> p $names 
BobJim 
  DB<42>

joseph4325
Novice

Jul 15, 2013, 10:49 AM

Post #3 of 6 (2084 views)

Re: [Laurent_R] regex/substitution on multiple cases [In reply to]	Can't Post

Thank you for the quick response. this worked perfectly.

BillKSmith
Veteran

Jul 15, 2013, 11:38 AM

Post #4 of 6 (2080 views)

Re: [joseph4325] regex/substitution on multiple cases [In reply to]	Can't Post

It can be done all at once. (I do not see an advantage to either method.)

Code

use strict; 
use warnings; 
my $names = "Bill and Steve and Jeff" ; 
my %sub = (Bill=>'Bob', Jeff=>'Jim'); 
$names =~ s/.*(Bill|Jeff).*(Bill|Jeff).*/$sub{$1}$sub{$2}/; 
print $names, "\n";

Good Luck,
Bill

2teez
Novice

Jul 15, 2013, 1:08 PM

Post #5 of 6 (2076 views)

Re: [joseph4325] regex/substitution on multiple cases [In reply to]	Can't Post

You can simply replace all the string like so:

Code

use warnings; 
use strict; 
 
my $names = "Bill and Steve and Jeff"; 
 
$names =~ s/.*/BobJim/; 
 
print $names, $/;

Laurent_R
Veteran / Moderator

Jul 15, 2013, 1:57 PM

Post #6 of 6 (2071 views)

Re: [2teez] regex/substitution on multiple cases [In reply to]	Can't Post

Yeah, sure, you can also do this:

Code

my $names = "Bill and Steve and Jeff";  
print "BobJim\n";

My first idea was to reply with the above, but I quickly decided to try to be more helpful.

If the instructor sees only the execution but not the code, it should yield a good mark.

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