如何統計兩次發生的頻率？

Question

所以我有一個數據集，看起來像這樣：

2,1,10,2,0 
2,1,23,2,1 
2,3,6,2,0 
5,1,4,3,0 
5,2,2,2,0 
5,2,2,3,1 
5,2,8,1,2 
5,3,6,3,1 
8,2,12,1,0 

我想有Perl打印的最後一個值在每一行的第2個值的每次出現。因此，例如，它是我的目標是有它打印以下：

2 1: 0 1 
2 3: 0 
5 1: 0 
5 2: 0 1 2 
5 3: 1 
8 2: 0 

我如何告訴Perl來打印行的最後一個值的數字配對的每次出現？

Answer 1

use strict; 
#use Data::Dumper; 
my $h; 

while (<>){ 
    chomp; 
    my @linechars = split /,/; 
    #Use the first two characters of the input line as the key to a hash. 
    my $key = $linechars[0]." ".$linechars[1]; 
    #stick the last character into an array for this key 
    push @{$h->{$key}}, $linechars[4]; 
} 

#print Dumper($h); 

foreach my $key (keys%{$h}){ 
    print "$key:"; 
    foreach (@{$h->{$key}}) 
    { 
     print " $_"; 
    } 
    print "\n"; 
} 

給人

-bash-3.2$ perl tmp.pl tmp.txt 
5 1: 0 
2 3: 0 
8 2: 0 
2 1: 0 1 
5 2: 0 1 2 
5 3: 1 

如果你只是想頻率，替換

foreach (@{$h->{$key}}) 
    { 
     print " $_"; 
    } 

與

print scalar (@{$h->{$key}})."\n" 

Answer 2

不知道你的頻率是什麼意思，但是這個代碼

#!perl 
use strict; 
use warnings; 

generate_output(2, 1); 
generate_output(2, 3); 
generate_output(5, 1); 
generate_output(5, 2); 
generate_output(5, 3); 
generate_output(8, 2); 

sub generate_output 
{ 
    my ($a, $b) = @_; 

    print "$a $b:"; 

    my $data_start = tell DATA; 

    while (<DATA>) { 
     chomp; 
     my @columns = split /,/; 
     if ($columns[0] == $a and $columns[1] == $b) 
     { 
      print " ", $columns[-1]; 
     } 
    } 
    print "\n"; 
    seek DATA, $data_start, 0; 
} 

__DATA__ 
2,1,10,2,0 
2,1,23,2,1 
2,3,6,2,0 
5,1,4,3,0 
5,2,2,2,0 
5,2,2,3,1 
5,2,8,1,2 
5,3,6,3,1 
8,2,12,1,0 

產生你想要的輸出：

2 1: 0 1 
2 3: 0 
5 1: 0 
5 2: 0 1 2 
5 3: 1 
8 2: 0