Question

可能重复：
Comparing Two Arrays Using Perl

如何打印@array2但不是@array1中存在的值？例如，给定：

@array1 = qw(1234567 7665456 998889 000909);
@array2 = qw(1234567 5581445 998889 000909);

输出应为：

5581445 doesn't exist in array1

Answer 1

my %tmp ;

# Store all entries of array2 as hashkeys (values are undef) using a hashslice
@tmp{@array2} = undef ; 

# delete all entries of array1 from hash using another hashslice
delete @tmp{@array1} ;
printf "In Array2 but not in Array1 : %s\n" , join( ',' , keys %tmp ) ;

Answer 2

使用smart matching（从5.10开始）无需编译自己的数组条目表：

print "$_  doesn't exist in array1\n" foreach grep { not $_ ~~ @array1 } @array2;

Answer 3

另一种方式是通过Array::Utils：

use strict;
use warnings;
use Array::Utils qw(array_minus);

my @array1= qw(1234567 7665456 998889 000909);
my @array2= qw(1234567 5581445 998889 000909);


my @not_in_a1=array_minus(@array2,@array1);

if(@not_in_a1)
{
    foreach(@not_in_a1)
    {
        print "$_ is in \@array2 but not in \@array1.\n";
    }
}
else
{
    print "Each element of \@array2 is also in \@array1.\n";
}

输出正是人们所期望的：

5581445 is in @array2 but not in @array1.

如何在@ array2中查找值，但不在@ array1中查找值

3 个答案: