Another approach depends on realizing that an expression like  my ($var1, $var2, ...) = ...; yields a list that can be processed with a Perl-ish for-loop. 

>perl -wMstrict -le
"my $str = 'a|  b||c  |  0  ';
 ;;
 $_ //= ''
   for my ($var1, $var2, $var3, $var4, $var5, $var6) =
     map Trim($_), split m{\|}xms, $str;
 ;;
 printf qq{'$_'  } for $var1, $var2, $var3, $var4, $var5, $var6;
 ;;
 sub Trim {
   $_[0] =~ s{ \A \s+ | \s+ \z }''xmsg;
   return $_[0];
   }
"
'a'  'b'  ''  'c'  '0'  ''

[download]

Use  defined or $_ = '' if you do not have the  //= operator (Perl 5.10+). Also, 5.14+ offers the  /r modifier for  s/// substitutions, which allows a slight simplification of the  Trim() function to
    sub Trim { return $_[0] =~ s{ \A \s+ | \s+ \z }''xmsgr; }

Also:
        ... am I correct in thinking that ... the parts of the string that are split will always be defined?
Yes.

In reply to Re: How to clean an array of strings after a split by AnomalousMonk
in thread How to clean an array of strings after a split by MrSnrub

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