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

  50545  4.393864E+00  .0   50546  9.589456E+00  .0
  50547  2.690474E+00  .0   50548 -1.668896E+01  .0
  50549 -3.391918E+01  .0   50550 -3.634581E+01  .0
  50551 -3.176630E+01  .0   50552 -1.747830E+01  .0
  50553 -5.256684E-01  .0   50554  1.135265E+01  .0

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I am trying to match between two integers. For example In the first line I tried to match anything between 50545 and 50546 and after 50546. In the first line I want to match "  4.393864E+00  .0" and stote it in "$1" and match "  9.589456E+00  .0" and store it in "$2". Do the same for the other lines. My code was: 
if($in =~ m/^\s+\d+\s+(.*)\d+\s+(.*)$/){
 print FH ("$1\n");
 print FH ("$2\n");
}

[download]
This code did not work. Can you help me?

Replies are listed 'Best First'.
Re: How can I match between two integer numbers
by davorg (Chancellor) on Jan 02, 2003 at 12:15 UTC

    This seems to give the answers you want

    /^\s+\d+\s+(.*?)\s+\d+\s+(.*?)$/;

    [download]

    It's worth looking at the $`, $& and $' variables to help you debug regular expressions.

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

    "The first rule of Perl club is you do not talk about Perl club."
    -- Chip Salzenberg

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[d/l]

      If he want match also leading space (" 4.393864E+00 .0" instead of "4.393864E+00 .0") I suggest

      /^\s+\d+\s(.*?)\s+\d+\s(.*?)$/
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[d/l]
[select]
        It's worth looking at the $`, $& and $' variables to help you debug regular expressions.

      It's relavant to note that the speed of the regexp code in Perl decreases when these variables are used.

      --t. alex
      Life is short: get busy!
[reply]

        Absolutely. Use them for debugging, but don't use them in production code - unless you really need to :)

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

        "The first rule of Perl club is you do not talk about Perl club."
        -- Chip Salzenberg

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Re: How can I match between two integer numbers
by talexb (Chancellor) on Jan 02, 2003 at 16:23 UTC

    Unless I've missed something, can't you just use split to get the job done?

    while (<DATA>)
{
  my @Data = split ( /\s+/ );
  print "Compare $Data[2] and $Data[5].\n";
}
__DATA__
  50545  4.393864E+00  .0   50546  9.589456E+00  .0
  50547  2.690474E+00  .0   50548 -1.668896E+01  .0
  50549 -3.391918E+01  .0   50550 -3.634581E+01  .0
  50551 -3.176630E+01  .0   50552 -1.747830E+01  .0
  50553 -5.256684E-01  .0   50554  1.135265E+01  .0

    [download]

    This code seems to work fine.

    --t. alex
    Life is short: get busy!

    Update: D'Oh! Sorry -- I thought the objective was to compare the numbers in exponent notation, not the integers before them. Thanks gjb.

[reply]
[d/l]

      Or, variation on the theme above, but keeping to what was asked (i.e. matching between the integer, not matching the individual real numbers): 

      while (<DATA>)
{
    chomp($_);
    my ($dummy, @Data) = split ( /\s+\d+\s+/ );
    print join(", ", @Data), "\n";
}
 
__DATA__
  50545  4.393864E+00  .0   50546  9.589456E+00  .0
  50547  2.690474E+00  .0   50548 -1.668896E+01  .0
  50549 -3.391918E+01  .0   50550 -3.634581E+01  .0
  50551 -3.176630E+01  .0   50552 -1.747830E+01  .0
  50553 -5.256684E-01  .0   50554  1.135265E+01  .0

      [download]

      Hope this helps, -gjb-

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[d/l]
Re: How can I match between two integer numbers
by hardburn (Abbot) on Jan 02, 2003 at 14:49 UTC

    You're probably having problems with the greedy-ness of .* and +. See also Death to Dot Star!.

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Re: How can I match between two integer numbers
by CountZero (Bishop) on Jan 02, 2003 at 16:47 UTC

    Activestate has Komodo a nice IDE for Perl (and other languages). It has a handy "real time" Regular Expression tool, which I use quite a lot to fiddle with Regexes.

    CountZero

    "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law

[reply]

      The original version is available from mjd's site as well.

      Personally I find that perl -de 0, setting $_, and incrementally piddling with x /foo(.*?)bar/ until I get something that matches works pretty well.

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[d/l]
[select]
Re: How can I match between two integer numbers
by JamesNC (Chaplain) on Jan 02, 2003 at 19:17 UTC
    Maybe this helps? 
    use strict;

while(<DATA>){
$_ =~s /\s+/:/ig;
my ($a, $b, $c, $d, $e, $f) = split /:/;
my $A = int scalar $a;    #marker
my $B = int scalar $b;    #data
my $C = int scalar $c;    #data
my $D = int scalar $d;    #marker
my $E = int scalar $e;    #$data
my $F = int scalar $f;    #$data

print "SCALAR: $a-> $b, $d-> $e\n";
print "INT PART: $A-> $B, $D-> $E\n";

# print FH "$B\n$E\n"; # your FH
}


__DATA__
50545  4.393864E+00  .0   50546  9.589456E+00  .0
50547  2.690474E+00  .0   50548 -1.668896E+01  .0
50549 -3.391918E+01  .0   50550 -3.634581E+01  .0
50551 -3.176630E+01  .0   50552 -1.747830E+01  .0
50553 -5.256684E-01  .0   50554  1.135265E+01  .0

    [download]
[reply]
[d/l]
Re: How can I match between two integer numbers
by osama (Scribe) on Jan 03, 2003 at 20:55 UTC
    why not just do something like this: 
    @fields=split(/\s+/);
print FH "$fields[1] $fields[2]\n";
print FH "$fields[4] $fields[5]\n";

    [download]
[reply]
[d/l]

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