Question

可能重复：
Perl sorting hash by values in the hash

我已经在网上浏览了很多解决方案，但我找不到满足我需求的东西。

我有一个很大的单词列表，每个单词附加了值

示例：

my %list = (
  word => 10,
  xword => 15,
  yword => 1
)

列表一直在继续，但我希望能够返回具有最高对应值的前5个哈希元素

Answer 1

use strict;
use warnings;

sub topN {
  my ($N, %list) = (shift, @_);
  $N = keys %list if $N > keys %list;
  return (sort { $list{$b} <=> $list{$a} } keys %list)[0..$N-1];
}

my %list = ( word => 10, xword => 15, yword => 1, zword => 4);     
print join (",", topN(5, %list)), "\n";

输出：

xword,word,zword,yword

Answer 2

这可以满足您的需求。请注意，如果您的哈希值少于五个元素，它将抛出Use of uninitialized value警告，您可能需要添加代码以满足该要求。它的效率也很低，因为它对整个哈希进行排序，而不是仅查找前五个值。这是否是一个问题取决于您的情况。

use strict;
use warnings;

my %list = (
  word => 10,
  xword => 15,
  yword => 1,
);

my @top5 = (sort { $list{$b} <=> $list{$a} } keys %list)[0..4];

print "$_\n" for @top5;

<强>输出

xword
word
yword

Answer 3

use strict;
use warnings;

my %list = (
   word => 10,
   xword => 15,
   yword => 1,
);

my @top5 = sort { $list{$b} <=> $list{$a} } keys %list;
splice(@top5, 5) if @top5 > 5;

print "$_\n" for @top5;

在perl中排序哈希值

3 个答案: