Question

给出以下数组：

#!/usr/local/bin/perl -w
use strict;
use warnings;
my $test1     = [['1005','bak','lah','blasck','reomhol'],
                ['1010','name','turd','furguson','reomhol'],
                ['1055','a','b','c','reomhol']];
my $test2     = [['1010','name','/home/roost/chicken.pm'],
                 ['1010','name','/home/roost/chicken2.pm'],
                 ['1010','name','/home/roost/chicken3.pm']];

my $match_array = [];
my $nomatch_arr = [];

我通过比较$ test1和$ test2创建了一个数组数组（$ match_array）。如果$ test1中每个数组的第一个元素与$ test2中每个数组的第一个元素匹配，那么一个条目将被推送到$ match_array。因此，应该有3个重复的条目。然后，我同时单步执行$ test2和$ match_arr，尝试将唯一的“位置”推送到$ match_array中的每个数组中。

my $flag = 0;

#foreach my $i (@$test1)
#my $tot = @$test1;
#$tot -= 1;
foreach my $i ( @$test1 ) 
{
    #print "line 25: $$i[0]\n\n\n";
    my $test2scalar = @$test2;
    for (my $j=0;$j<$test2scalar;$j++)
    {
        #print "line 29: $test2->[$j][0]\n";
        if($$i[0] == $test2->[$j][0])
        {
            push(@$match_array,$i);
            $flag += 1;
        }
    }
    if ($flag == 0)
    {
        push(@$nomatch_arr,$i);
    }
}
print "------------------------Initial Output----------------------------\n";
for (my $k=0;$k<@$match_array;$k++)
{
    print "$k-->@{$match_array->[$k]}\n";
}
print "------------------------Begin Push----------------------------\n";
for (my $count=0;$count<@$test2;$count++)
{
     print "$test2->[$count][2]\n";
     print "$count => @{$match_array->[$count]}\n";
     push(@{$match_array->[$count]}, $test2->[$count][2]);
}
print "------------------------Final Output----------------------------\n";
for (my $k=0;$k<@$match_array;$k++)
{
    print "$k-->@{$match_array->[$k]}\n";
}

为什么当使用push(@{$match_array->[$count]}, $test2->[$count][2]);时，它会将唯一位置推送到$ match_array的每个数组中？

输出：

------------------------Initial Output----------------------------
0-->1010 name turd furguson reomhol
1-->1010 name turd furguson reomhol
2-->1010 name turd furguson reomhol
------------------------Begin Push----------------------------
unique location: /home/roost/chicken.pm
array element: 0 => 1010 name turd furguson reomhol
unique location: /home/roost/chicken2.pm
array element: 1 => 1010 name turd furguson reomhol /home/roost/chicken.pm
unique location: /home/roost/chicken3.pm
array element: 2 => 1010 name turd furguson reomhol /home/roost/chicken.pm /home/roost/chicken2.pm
------------------------Final Output----------------------------
0-->1010 name turd furguson reomhol /home/roost/chicken.pm /home/roost/chicken2.pm /home/roost/chicken3.pm
1-->1010 name turd furguson reomhol /home/roost/chicken.pm /home/roost/chicken2.pm /home/roost/chicken3.pm
2-->1010 name turd furguson reomhol /home/roost/chicken.pm /home/roost/chicken2.pm /home/roost/chicken3.pm

Answer 1

我只是想补充一下以帮助下一个人

此问题的一个易于复制的示例：

let foo = Array(3).fill([]) //creates an array with three empty arrays inside
foo[0].push('bar') //[['bar'],['bar'],['bar']]

对比

let foo = [[],[],[]] //creates an array with three empty arrays inside it
foo[0].push('bar') // [['bar'],[],[]]

将唯一条目推入数组数组中的数组实际上会将条目推入数组数组中的每个数组？

1 个答案: