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Re^3: how to open a data file via http

by pKai (Priest)
on Feb 27, 2007 at 15:26 UTC ( #602307=note: print w/replies, xml ) Need Help??


in reply to Re^2: how to open a data file via http
in thread how to open a data file via http

split(/\n/, $data) doesn't work. It removes blank trailing lines.

What is your definition of "doesn't work" here? The dropping of empty trailing fields in the case of the LIMIT parameter being 0 or not specified works as advertised in the split docs.

split(/\n/, $data, -1) doesn't work either. It adds a blank line.

Perl doesn't do this on my system:

>perl -MData::Dumper -e "$_=qq(1\n2\n3); print Dumper split /\n/,$_,-1 +" $VAR1 = '1'; $VAR2 = '2'; $VAR3 = '3'; >perl -MData::Dumper -e "$_=qq(1\n2\n3\n); print Dumper split /\n/,$_, +-1" $VAR1 = '1'; $VAR2 = '2'; $VAR3 = '3'; $VAR4 = '';

When you read your data from file on the other hand, you have to be careful that your editor does not hide a trailing newline on the display. (E.g. Vim, where you can't tell the difference, other than by an initial [noeol] in the status line.)

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Re^4: how to open a data file via http
by ikegami (Pope) on Feb 27, 2007 at 16:39 UTC

    What is your definition of "doesn't work" here?

    The goal was a replacement for <FILE>, so anything that doesn't return what <FILE> is buggy. In hangon's favour, I didn't consider autochomping a bug.

    my $data = "\n" # 1 . "abc\n" # 2 . "def\n" # 3 . "\n" # 4 . "\n" # 5 . "ghi\n" # 6 . "\n" # 7 . "\n"; # 8 { print("<FILE>\n"); my $lines = 0; open(my $fh, '<', \$data); while (<$fh>) { ++$lines; chomp; print("[$_]\n"); } print($lines, "\n"); } print("\n"); { print("split(/\n/, \$data)\n"); my $lines = 0; foreach (split(/\n/, $data)) { ++$lines; print("[$_]\n"); } print($lines, "\n"); } print("\n"); { print("split(/\n/, \$data, -1)\n"); my $lines = 0; foreach (split(/\n/, $data, -1)) { ++$lines; print("[$_]\n"); } print($lines, "\n"); } print("\n"); { print("split(/^/m, \$data)\n"); my $lines = 0; foreach (split(/^/m, $data, -1)) { ++$lines; chomp; print("[$_]\n"); } print($lines, "\n"); }

    outputs

    <FILE> [] [abc] [def] [] [] [ghi] [] [] 8 <-- This is what <FILE> gives. split(/\n/, $data) [] [abc] [def] [] [] [ghi] 6 <-- Not 8. Failed to emulate <FILE>. split(/\n/, $data, -1) [] [abc] [def] [] [] [ghi] [] [] [] <-- Extra line 9 <-- Not 8. Failed to emulate <FILE>. split(/^/m, $data) [] [abc] [def] [] [] [ghi] [] [] 8 <-- Bingo!

    wc -l says 8 as well, by the way.

    Perl doesn't do this on my system:

    uh, yes it does... $VAR4 = '';. Lines aren't *seperated* by newlines, they are *terminated* by them.

      The goal was a replacement for <FILE>, so anything that doesn't return what <FILE> would is buggy. … I didn't consider autochomping a bug.

      O.K., that clarification gives me enough context where you were heading to.

      An added chomp($data) before the split /\n/,,-1 will also conform to that abstraction of lines.

      Update: Added the missing ,-1

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