如何从Perl中的整数列表中获取范围？

Question

我有一个数字数组：

@numbers = 1,2,3,6,8,9,11,12,13,14,15,20 

，我想打印这样说：

1-3,6,8-9,11-15,20 

有什么想法？当然，我尝试使用最常见的“循环”，但仍然没有得到它。

Answer 1

这里是一个可能的方式：

@numbers = (1,2,3,6,8,9,11,12,13,14,15,20); 
@list =(); 
$first = $last = shift @numbers; 
foreach (@numbers,inf) { 
    if ($_ > $last+1) { 
    if ($first == $last) { 
     push @list, $first; 
    } elsif ($first+1 == $last) { 
     push @list, $first, $last; 
    } else { 
     push @list, "$first-$last"; 
    } 
    $first = $_; 
    } 
    $last = $_; 
} 

print join ',', @list; 

Answer 2

您可以使用Set::IntSpan::Fast：

use Set::IntSpan::Fast; 

my @numbers = (1,2,3,6,8,9,11,12,13,14,15,20); 

my $set = Set::IntSpan::Fast->new; 
$set->add(@numbers); 
print $set->as_string, "\n"; 

Answer 3

@numbers=sort { $a <=> $b } @numbers; 
push @numbers, inf; 

@p=(); 
$ra = shift @numbers; 
$rb = $ra; 
for $n (@numbers) { 
    if ($n > $rb +1) { 
     push @p, ($ra == $rb ? "$ra" : "$ra-$rb"); 

     $ra = $n; 
    } 

    $rb = $n; 
} 

print join(',', @p);