Perl：比较两个CSV文件和打印差异 [英] Perl: Compare Two CSV Files and Print out differences

问题描述

我是Perl的noob，我很难做到这一点。我有两个单列的CSV文件，我试图打印差异到第三个文件。

I'm a noob in Perl and I'm having a tough time getting this done. I have two single-columned CSV files, and I'm trying to print the differences to a third file.

File1:
123
124
125
126

File2:
123
124
127

Expected Output:
125
126
127

是我到目前为止，这是不工作：

This is what I've got so far, which isn't working:

#!/usr/bin/perl

use strict;
use warnings;

my $sheet_1;
my $sheet_2;
my $count1 = 0;
my $count2 = 0;

my $file1 = 'file1.csv';
my $file2 = 'file2.csv';
my $file_out = 'output.csv';

open (FILE1, "<$file1")  or die "Couldn't open input file: $!"; 
open (FILE2, "<$file2")  or die "Couldn't open input file: $!"; 


while( <FILE1> ) {
  chomp;
  $count1++;
  #skip header;
  next unless $count1;
  my $row_1;
  @$row_1 = split( /,/, $_ );
  push @$sheet_1, $row_1;
}
@$sheet_1 = sort { $a->[0] <=> $b->[0] } @$sheet_1;

while( <FILE2> ) {
  chomp;
  $count2++;
  #skip header;
  next unless $count2;
  my $row_2;
  @$row_2 = split( /,/, $_ );
  push @$sheet_2, $row_2;
}

@$sheet_2 = sort { $a->[0] <=> $b->[0] } @$sheet_2;


OUTER: {
     foreach my $row_1 ( @$sheet_1 ) {
         foreach my $row_2 ( @$sheet_2 ) {
        if (@$row_1[0] eq @$row_2[0]){
        last OUTER
        }
        else{
        print "@$row_1[0]\n";
        }
        }
    }
}

close FILE1;
close FILE2;

推荐答案

您可以使用 Text :: Diff Perl模块来做到这一点。否则，请参阅以下内容：

You can use the Text::Diff Perl module to do this. Otherwise, see below:

这里有一种算法来进行比较。

Here's one algorithm to do the comparison.

use strict;
my @arr1;
my @arr2;
my $a;

open(FIL,"a.txt") or die("$!");
while (<FIL>)
    {chomp; $a=$_; $a =~ s/[\t;, ]*//g; push @arr1, $a if ($a ne  '');};
close(FIL);

open(FIL,"b.txt") or die("$!");
while (<FIL>)
    {chomp; $a=$_; $a =~ s/[\t;, ]*//g; push @arr2, $a if ($a ne  '');};
close(FIL);

my %arr1hash;
my %arr2hash;
my @diffarr;
foreach(@arr1) {$arr1hash{$_} = 1; }
foreach(@arr2) {$arr2hash{$_} = 1; }

foreach $a(@arr1)
{
    if (not defined($arr2hash{$a})) 
     {
        push @diffarr, $a;
     }
}

foreach $a(@arr2)
{
   if (not defined($arr1hash{$a})) 
   { 
       push @diffarr, $a;
   }
}

print "Diff:\n";
foreach $a(@diffarr)
{
    print "$a\n";
}
# You can print to a file instead, by: print FIL "$a\n";

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