arrays - Perl 数组对相似元素求和

Question

我有一个由字符串和数字组成的数组。我想对那些具有相似字符串值的数字求和。请帮忙！！

文件：

aggr3 350.01000213623
aggr3 1228.79999923706
aggr5 250
aggr3 1536
aggr3 690.01000213623
aggr3 1587.20000076294
aggr9 550.01000213623
aggr3 1228
aggr5 905
aggr5 100

所需输出

aggr3 5391
aggr5 1255
aggr9 550

Answer 1

大概是这样？

use strict;
use warnings;

my @data = <DATA>;
my %data;
$data{$_->[0]} += $_->[1] for map [ split ], @data;

print "$_ $data{$_}\n" for sort keys %data;

__DATA__
aggr3 350.01000213623
aggr3 1228.79999923706
aggr5 250
aggr3 1536
aggr3 690.01000213623
aggr3 1587.20000076294
aggr9 550.01000213623
aggr3 1228
aggr5 905
aggr5 100

输出

aggr3 6620.02000427246
aggr5 1255
aggr9 550.01000213623

Answer 2

通常，如果你想在 Perl 中对一些数据进行分组，你会使用 hashes。这些散列的键对应于分组标准，值用作累加器（它可以是一个简单的数字，如本例所示，也可以是等待稍后处理的数字数组）。

这是一种方法：

use warnings;
use strict;

# this hash will hold all the cumulatives
my %sums;

# here we scan the source, line by line
# each line is split to key and value
while (<DATA>) {
  chomp;
  my ($label, $value) = split;

  # this line uses the auto-vivification Perl feature:
  # if there's no corresponding item in %sums hash, it'll be created (with 0 value)
  $sums{$label} += $value;
}

# here we process the resulting hash:
for my $key (sort keys %sums) {
  print $key, ' ', $sums{$key}, "\n";
}
__DATA__
aggr3 350.01000213623
aggr3 1228.79999923706
aggr5 250
aggr3 1536
aggr3 690.01000213623
aggr3 1587.20000076294
aggr9 550.01000213623
aggr3 1228
aggr5 905
aggr5 100

键盘演示。