split a string at a defined index

avanta has asked for the wisdom of the Perl Monks concerning the following question:

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Re: split a string at a defined index by BrowserUk (Patriarch) on Mar 29, 2010 at 06:18 UTC
You can split at the last comma by using a lookahead to check there are no more commas: `print for split /,(?=[^,]+$)/, "www,google,yahoo,345";; www,google,yahoo 345` [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "I'd rather go naked than blow up my ass"	[reply] [d/l]
Re^2: split a string at a defined index by AnomalousMonk (Archbishop) on Mar 29, 2010 at 08:09 UTC
... and `split` on a specific index (without using substr): `>perl -wMstrict -le "my $s = 'www,google,yahoo,345'; my ($v1, $v2) = split m{ (?<= \A .{16}) , }xms, $s; print qq{[$v1] [$v2]}; " [www,google,yahoo] [345]` [download]	[reply] [d/l] [select]
Re^3: split a string at a defined index by BrowserUk (Patriarch) on Mar 29, 2010 at 08:19 UTC
I suspect that by "at a defined index", the IP meant "the third comma" rather than "the 16th character position". If he does mean the 16th position, using substr is far clearer and vastly more efficient. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "I'd rather go naked than blow up my ass"	[reply]
Re: split a string at a defined index by wfsp (Abbot) on Mar 29, 2010 at 07:15 UTC
You don't always have to use a regex (in split or otherwise). :-) `#! /usr/bin/perl use strict; use warnings; my $line = q{www,google,yahoo,345}; my $comma = rindex($line, q{,}); print substr($line, 0, $comma), qq{\n}; print substr($line, $comma+1);` [download]	[reply] [d/l]
Re: split a string at a defined index by almut (Canon) on Mar 29, 2010 at 07:16 UTC
Another one (using rindex): `sub mysplit { my $s = shift; my $p = rindex $s, ','; return ( substr($s,0,$p), substr($s,$p+1) ); } my ($var1, $var2) = mysplit('www,google,yahoo,345');` [download]	[reply] [d/l]
Re: split a string at a defined index by CountZero (Bishop) on Mar 29, 2010 at 06:40 UTC
And one more solution: `use strict; use warnings; while (my $row = <DATA>) { chomp $row; my @elements = split ',', $row; my $tail = pop @elements; my $body = join ',', @elements; print "$body -- $tail\n"; } __DATA__ www,google,yahoo,345 www,google,yahoo,75323` [download] CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James	[reply] [d/l]
Re: split a string at a defined index by Anonymous Monk on Mar 29, 2010 at 05:50 UTC
There are more concise solutions, but few as mappily delicious as this one: `my ($var1, $var2) = reverse # reverse order of split strings map {scalar reverse} # reverse characters back map { split(/,/, $_, 2) } # split off first field map {scalar reverse} # reverse characters qq(www,google,yahoo,345) # string ;` [download] `# perl -le'print for reverse map {scalar reverse} map { split(/,/, $_, + 2) } map {scalar reverse} qq(www,google,yahoo,345);' www,google,yahoo 345` [download]	[reply] [d/l] [select]
Re: split a string at a defined index by Punitha (Priest) on Mar 29, 2010 at 05:32 UTC
Hi AvantA, Try this `$str="www,google,yahoo,345"; my ($var1,$var2)= $str =~/^([^\n]+),([^\n]+)$/;` [download] Punitha	[reply] [d/l]
Re^2: split a string at a defined index by smokemachine (Hermit) on Mar 29, 2010 at 10:58 UTC
`/^(.+),(.+?)$/` [download]	[reply] [d/l]
Re: split a string at a defined index by JavaFan (Canon) on Mar 29, 2010 at 14:11 UTC
`$var1 = "www,google,yahoo,345"; $var1 =~ s/,([^,]*)\z//; $var2 = $1;` [download]	[reply] [d/l]