如何在Perl中计算csv中具有相同id的项目数

是的,哈希是正确的数据结构。

#!/usr/bin/perl
use warnings;
use strict;

my %count;
while (<DATA>) {
    chomp;
    my ($user, $group) = split /:/;
    ++$count{$group};
}

for my $group (keys %count) {
    print "Group $group has $count{$group} members.\n";
}

__DATA__
x:2
y:2
z:4
p:1
q:4