How can I split a Perl string only on the last occurrence of the separator?

Question

Hi All,

my $str="1:2:3:4:5";
my ($a,$b)=split(':',$str,2);

In the above code I have used limit as 2 ,so $a will contain 1 and remaining elements will be in $b. Like this I want the last element should be in one variable and the elements prior to the last element should be in another variable.

Example

$str = "1:2:3:4:5" ; 
# $a should have "1:2:3:4"  and $b should have "5" 
$str =  "2:3:4:5:3:2:5:5:3:2" 
# $a should have "2:3:4:5:3:2:5:5:3" and $b should have "2"

Answer 1

split(/:([^:]+)$/, $str)

Answer 2

You can do it using split and reverse as follows:

my $str="1:2:3:4:5";
my ($a,$b)=split(':',reverse($str),2); # reverse and split.

$a = reverse($a); # reverse each piece.
$b = reverse($b);

($a,$b) = ($b,$a); # swap a and b

Now $a will be 1:2:3:4 and $b will be 5.

A much simpler and cleaner way is to use regex as Mark has done in his Answer.

Answer 3

you can also use rindex() eg

my $str="1:2:3:4:5";
$i=rindex($str,":");
$a=substr($str,0,$i);
$b=substr($str,$i+1);
print "\$a:$a, \$b: $b\n";

output

$ perl perl.pl
$a:1:2:3:4, $b: 5

Answer 4

You can use matching, instead of split:

my ($a,$b) = $str =~ /(.*):(.*)/;