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Split string into equal parts

by kalyanrajsista (Scribe)
on May 28, 2010 at 16:39 UTC ( #842072=perlquestion: print w/replies, xml ) Need Help??
kalyanrajsista has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks

I've tried the following code in splitting a string into 4 equal parts separated by a space. I've looking for a good method to refine my code or suggest a good way to do....

use strict; my $tempStr = 'BE65826000483296'; my $tempStr1; while ( $tempStr . length ) { $tempStr1 .= " " . substr( $tempStr, 0, 4 ); $tempStr = substr( $tempStr, 4 ); } $tempStr1 =~ s/^\s//isg; print $tempStr1;

Many Thanks

Replies are listed 'Best First'.
Re: Split string into equal parts
by BrowserUk (Pope) on May 28, 2010 at 16:44 UTC

    You're working way too hard:

    $tempStr = 'BE65826000483296'; print join ' ', unpack '(A4)*', $tempStr; BE65 8260 0048 3296
      Thanks BrowserUK, Your one-liner solves my problem
Re: Split string into equal parts
by ikegami (Pope) on May 28, 2010 at 16:48 UTC

      For those still stuck in 5.8-dom, it's possible to do this substitution without use of the  \K special escape of 5.10:

      >perl -wMstrict -le "for (@ARGV) { (my $sp = $_) =~ s{ (.{4}) (?= .) }{$1 }xmsg; print qq{'$_' -> '$sp'}; } " "" A ABC ABCD ABCDa ABCDabc ABCDabcd ABCDabcdE '' -> '' 'A' -> 'A' 'ABC' -> 'ABC' 'ABCD' -> 'ABCD' 'ABCDa' -> 'ABCD a' 'ABCDabc' -> 'ABCD abc' 'ABCDabcd' -> 'ABCD abcd' 'ABCDabcdE' -> 'ABCD abcd E'

      This approach is likely less efficient due to use of a capture. Is it possible to do this operation in a pre-5.10 solo substitution (i.e., no  m//  unpack  join   etc.) without a capture and in a fairly simple way (for some definition of 'fairly simple')?

      Thank you ikegami, You're one-liner is awe-some but unfortunately I'm still using Perl 5.8.8 and thus unable to use your solution. Just curious to know any other solution which works in any version of Perl
Re: Split string into equal parts
by johngg (Abbot) on May 28, 2010 at 20:44 UTC

    Another way would be to use substr to insert spaces working back from the right-hand end of the string.

    $ perl -E ' > $str = q{abcdefghijklmn}; > say $str; > substr $str, $_, 0, q{ } for > grep { ! ( $_ % 4 ) } reverse 4 .. length( $str ) - 1; > say $str;' abcdefghijklmn abcd efgh ijkl mn $

    I hope this is of interest.



Re: Split string into equal parts
by proceng (Scribe) on May 28, 2010 at 20:24 UTC
    splitting a string into 4 equal parts separated by a space
    You would need to get the length of the string and divide it by 4. However, your (not so) edge case is where you do not have a length that is a multiple of 4 (think wep keys).
    How do you want to handle that?

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