Re^2: Global array afftected by map inside of a subroutine

ikegami...List::MoreUtils's apply did exactly what I needed for the array. Thank you! Now all I need to figure out is why my grep is breaking.

I isolated the code that I am working on, but grep is grepping everything. I've never had this problem with grep before.

my @filesize_names = qw(bit nibble byte kilobyte megabyte gigabyte ter
+abyte petabyte exabyte zettabyte yottabyte);

  my $word = 'fubar';
     $word =~ s/s$//;

  my @short_sizes = apply {$_ =~ s/^(\w)\w{1,}$/$1b/} @filesize_names;

  print Dumper(\@filesize_names);
  print Dumper(\@short_sizes);

  if (grep(lc $word,@short_sizes)) { # even 'fubar' greps
    print "$word grepped!";
    $word = $filesize_names[firstidx { $_ eq lc $word } @short_sizes];
  }

  print $word;
[download]

Have a cookie and a very nice day!

Lady Aleena

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Re^3: Global array afftected by map inside of a subroutine by BrowserUk (Patriarch) on Dec 14, 2011 at 21:36 UTC
grep is grepping everything. I've never had this problem with grep before. You are using: `grep( lc $word, @short_sizes )` [download] grep passes through any value where the expression (first argument) is true. Your grep expression is `lc $word`. If `$word` has any value except `undef`, `''` or `0`, then `lc $word` will also have a value, and therefore be true, and everything in `@short_sizes` will pass through. Since `if( grep( ...,... ) ) {` places grep in a scalar context, the result will be the number of items passed through, which will be the same as the number of elements in `@short_sizes`. So, unless it is empty, the if condition will be true. Effectively, `if (grep(lc $word,@short_sizes)) {` is the same as:`if( defined( $word ) && @short_sizes > 0 ) {` which almost certainly isn't what you intend. So, what are you trying to achieve with that construct? If you are trying to check if any of the values in `@short_sizes` matches the lower cased value of `$word`, the you would need: `if( grep( $_ eq lc $word, @short_sizes ) ) {` [download] But that's just my guess as to your intent. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' 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. The start of some sanity?	[reply] [d/l] [select]
Re^4: Global array afftected by map inside of a subroutine by Lady_Aleena (Priest) on Dec 14, 2011 at 21:48 UTC
BrowserUk...you guessed correctly. Thank you! *Have a cookie and a very nice day!* Lady Aleena	[reply]
Re^3: Global array afftected by map inside of a subroutine by kejohm (Hermit) on Dec 14, 2011 at 21:59 UTC
Based on your code sample, might I suggest a hash lookup table, eg: `# Untested my @filesize_names = qw(kilobyte megabyte gigabyte terabyte petabyte e +xabyte zettabyte yottabyte); my %short_sizes = map { m/^(\w)/; $1 . 'b' => $_ } @filesize_names; my $word = 'kb'; if ( exists $short_sizes{lc $word} ) { say $short_sizes{lc $word}; }` [download]	[reply] [d/l]