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

Dear brethren,

here is my problem. I have a string, say 'E/stYna~ko/', and I want to split it into single letters, except '/' and '~' should be grouped with the preceding letter (they never appear at the beginning of the string) I.e. the desired output in the above case is 'E/ s t Y n a~ k o/'. Sounds like a job for split, right? Only that I can't get it to work properly. Here's what I have tried so far: 

$x = 'E/stYna~ko';
print join (' ', split /(\w[^\/~])/, $x); #->E/ st  Yn a~ ko /
print join (' ', split /(\w(?!\/~))/, $x); #-> E / s  t  Y  n  a ~ k  
+o
print join (' ', split /([^\/~])/, $x); #-> E / s  t  Y  n  a ~ k  o
print join (' ', split /(?!\/~)/, $x); #->E / s t Y n a ~ k o

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Yes, I know I could first split into individual characters and then go through the array and join the '/' and '~' with the preceding characters, but can't split give me the correct solution right away?

Puzzled, pike

Replies are listed 'Best First'.
Re: split this
by davorg (Chancellor) on Nov 06, 2001 at 17:52 UTC

    Actually, it doesn't sound like a job for split. It sounds like a job for a regular expression. Try this:

    my $x = 'E/stYna~ko';

my @chars = $x =~ /(\w\W*)/g;

print "@chars\n";

    [download]
    --
    <http://www.dave.org.uk>

    "The first rule of Perl club is you don't talk about Perl club."

[reply]
[d/l]

      split /(?=\w)/ also works.

              - tye (but my friends call me "Tye")
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[d/l]

      Bravo! Succinct, concise, nothing unnecessary. Well done.

      dmm

      
You can give a man a fish and feed him for a day ...
Or, you can teach him to fish and feed him for a lifetime
[reply]
Re: split this
by Tyke (Pilgrim) on Nov 06, 2001 at 18:02 UTC
    I think that you _can_ do it with a split: 
    perl -le "print for split /(?=[^~\/](?:.|$))/,shift" "E/sYna~ko/"

    [download]
    looks as if it works on your test data.

    Update Actually that should have been 

    perl -le "print for split /(?=[^~\/])/,shift" "E/sYna~ko/"

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    but you saw that
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[d/l]
[select]
Re: split this
by Elliott (Pilgrim) on Nov 06, 2001 at 17:54 UTC
    The following groups them correctly but is still inserting extra blanks. 

    $x = 'E/stYna~ko';
@j=split (/(\w\W*)/, $x);
foreach $j(@j){
$i++;
   print "$i - $j\n";
}
print "\n";

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    (I added the extra code for clarity of output. It was hard to see where the exrta blanks were otherwise.)

[reply]
[d/l]
      Almost what I was looking for. I just have to grep out the empty fields: 

      print join(':', grep /\S/, split /(\w\W?)/,$x); #->E/:s:t:Y:n:a~:k:o

      [download]
      And yes, using blanks as delimiters in the print was a bad idea -> changed to colons.

      Thanks, pike

[reply]
[d/l]
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[d/l]
        {
  local $" = "', '";
  print "'@j'\n";
}

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        perlvar is your friend :)

        Update: Well, OK. Maybe not more concise then. But, maybe easier to follow?

        I think we need a shorter alias for local.

        --
        <http://www.dave.org.uk>

        "The first rule of Perl club is you don't talk about Perl club."

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[d/l]
Re: split this
by BrentDax (Hermit) on Nov 07, 2001 at 00:02 UTC 
    C:\WINDOWS\Desktop>perl -e "print join ' ', split /(?!\W)/, 'E/sYna~ko
+/'"
E/ s Y n a~ k o/

    [download]

    Your example like this forgot to use a character class--it tried to match a slash followed by a tilde.

    =cut
    --Brent Dax
    There is no sig.

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[d/l]

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