我有一个如下的数组引用：
my $strings = [qw(a b c d)];
我想形成所有可能的组合并创建一个数组数组：
my $output = [qw(qw([a],[b],[c],[d],[a,b],[a,c],[a,d],[b,c],[b,d],[c,d], [a,b,c],[a,b,d],[b,c,d],[a,b,c,d]))]
我尝试了什么：
foreach my $n(1..scalar(@array)) {
my $iter = combinations($strings, $n);
while (my $c = $iter->next) {
print "@$c\n";
}
}
【问题讨论】：
标签： arrays perl perl-module perl-data-structures
如果您手头没有模块，并且不关心外层顺序：
sub fu {
my ($base,@rest) = @_;
my @result = @$base && $base || ();
push @result, fu( [@$base, shift @rest], @rest) while @rest;
return @result;
}
my @output = fu([],qw(a b c d));
@output的内容：
[["a"],["a","b"],["a","b","c"],["a","b","c","d"],["a","b","d"],["a","c"],["a","c","d"],["a","d"],["b"],["b","c"],["b","c","d"],["b","d"],["c"],["c","d"],["d"]]
【讨论】：
#!/usr/bin/perl
use strict;
use warnings;
use Math::Combinatorics qw(combine);
use Data::Dumper;
my @n = qw(a b c d);
my @res;
push @res, combine($_, @n) foreach (0..@n);
print Dumper(\@res);
输出：
$VAR1 = [
[
'b'
],
[
'c'
],
[
'a'
],
[
'd'
],
[
'c',
'a'
],
[
'c',
'd'
],
[
'c',
'b'
],
[
'a',
'd'
],
[
'a',
'b'
],
[
'd',
'b'
],
[
'b',
'a',
'd'
],
[
'b',
'a',
'c'
],
[
'b',
'd',
'c'
],
[
'a',
'd',
'c'
],
[
'b',
'c',
'd',
'a'
]
];
【讨论】：
使用Algorithm::Combinatorics 查找所有组合。
#!/#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use Algorithm::Combinatorics qw(combinations);
my @data = qw(a b c d);
my $all_combinations;
foreach (1..4){
push @$all_combinations, combinations(\@data, $_);
}
print Dumper $all_combinations;
输出：
$VAR1 = [
[
'a'
],
[
'b'
],
[
'c'
],
[
'd'
],
[
'a',
'b'
],
[
'a',
'c'
],
[
'a',
'd'
],
[
'b',
'c'
],
[
'b',
'd'
],
[
'c',
'd'
],
[
'a',
'b',
'c'
],
[
'a',
'b',
'd'
],
[
'a',
'c',
'd'
],
[
'b',
'c',
'd'
],
[
'a',
'b',
'c',
'd'
]
];
【讨论】：
您可以使用模块“Algorithm::Combinatorics”
use Algorithm::Combinatorics "variations_with_repetition";
my @Variations = variations_with_repetition([qw(a b c d)], 4);
print "@$_\n", for @Variations;
【讨论】：