Split string into equal parts

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;
[download]

Many Thanks

Comment on Split string into equal parts Download Code

Replies are listed 'Best First'.
Re: Split string into equal parts by BrowserUk (Patriarch) 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` [download]	[reply] [d/l]
Re^2: Split string into equal parts by kalyanrajsista (Scribe) on May 29, 2010 at 13:58 UTC
Thanks BrowserUK, Your one-liner solves my problem	[reply]
Re: Split string into equal parts by ikegami (Patriarch) on May 28, 2010 at 16:48 UTC
`s/.{4}\K(?=.)/ /sg;` [download]	[reply] [d/l]
Re^2: Split string into equal parts by AnomalousMonk (Archbishop) on May 28, 2010 at 19:31 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'` [download] 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')?	[reply] [d/l] [select]
Re^2: Split string into equal parts by kalyanrajsista (Scribe) on May 29, 2010 at 13:57 UTC
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	[reply]
Re^3: Split string into equal parts by ikegami (Patriarch) on May 31, 2010 at 03:29 UTC
`s/.{4}\K(?=.)/ /sg;` [download] is an optimisation of `s/(.{4})(?=.)/$1 /sg;` [download]	[reply] [d/l] [select]
Re: Split string into equal parts by johngg (Canon) on May 28, 2010 at 20:44 UTC
Another way would be to use substr to insert spaces working back from the right-hand end of the string. `$ 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 $` [download] I hope this is of interest. Cheers, JohnGG	[reply] [d/l]
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?	[reply]