在 XXXX 中的串联 (.) 中使用未初始化的值，或在 XX 行image_magick.pl使用字符串

Question

我编写了一个程序来比较两个文件夹的图像文件（每个文件夹有 1000 个文件）与一些逻辑（请参阅此 SO 问题）。

执行它时成功比较直到 900 张图像，但随后它会给出Use of uninitialized value within @tfiles2 in concatenation (.) or string at C:dropboxImage_Compareimage_magick.pl line 55 之类的错误。然后我收到一个弹出错误，例如 Perl Command Line Interpreter has stopped working ，所以我关闭了程序。

我的代码如下：

#!/usr/bin/perl
 use Image::Magick;
 no warnings 'uninitialized';
 use warnings;
 use diagnostics;
#use strict;
 use List::Util qw(first);
    my $directory1="C:/dropbox/Image_Compare/folder1";
    opendir(DIR, $directory1) or die "couldn't open $directory1: $!n";
    my @files1 = grep { (!/^./) && -f "$directory1/$_" } readdir(DIR);
    closedir DIR;
    print @files1;
    print 'end of files1';
    my $directory2="C:/dropbox/Image_Compare/folder2";
    opendir(DIR, $directory2) or die "couldn't open $directory2: $!n";
    my @files2= grep { (!/^./) && -f "$directory2/$_" } readdir(DIR);
    closedir DIR;
    print @files2;
    print 'end of files2';
    print $files1[0];
    foreach my $fils2 (@files2)
    {
        $g1 = Image::Magick->new;
        $g2 = Image::Magick->new;
        $temp1 = $g1->Read( filename=>"C:/dropbox/Image_Compare/folder1/".$files1[0].""); 
        $temp1 = $g2->Read( filename=>"C:/dropbox/Image_Compare/folder2/".$fils2."");
        $g3 = $g1->Compare( image=>$g2, metric=>'AE' ); # compare
        $error1 = $g3->Get( 'error' );
        #print $error1;
        if ($error1 == '0') 
        {
            print "Matching image is:"; 
            print $fils2 . "n"; 
            my $tdirectory2="C:/dropbox/Image_Compare/folder2";
            opendir(DIR, $tdirectory2) or die "couldn't open $directory2: $!n";
            my @tfiles2 = grep { (!/^./) && -f "$tdirectory2/$_" } readdir(DIR);
            closedir DIR;
            #my $index = firstidx { $_ eq'"' .$fils2.'"' } @tfiles2;
            my $index = first { $tfiles2[$_] eq $fils2} 0..$#tfiles2;
            #print $fils2;
            print $index;
            my $i=0;
            foreach my $fils1 (@files1)
            {
                print 'ganesh';
                print $files1[$i];
                print $tfiles2[$index];
                print 'gowtham'; print "<br />";
                #print @tfiles2;
                $g4 = Image::Magick->new;
                $g5 = Image::Magick->new;
                $temp2 = $g4->Read( filename=>"C:/dropbox/Image_Compare/folder1/".$files1[$i].""); 
                $temp2 = $g5->Read( filename=>"C:/dropbox/Image_Compare/folder2/".$tfiles2[$index]."");
                $g6 = $g4->Compare( image=>$g5, metric=>'AE' ); # compare
                $error2 = $g6->Get( 'error' );
                $i++;
                $index++;
                if ($error2 == '0') {}
                else {print "Image not matching:"; print $tfiles2[$index]; last;}
                #if ($i == '800') {last;}

            }
            last
        }
    }

谁能帮忙，我在哪里做错了。

文件夹 1 文件名：0025.bmp 到 1051.bmp;

文件夹 2 文件名：0000.bmp 到 1008.bmp;

谢谢加内什

Answer 1

我不知道

哪一行是冒犯的，但其中一个可能是候选者：

$temp2 = $g5->Read( filename=>"C:/dropbox/Image_Compare/folder2/".$tfiles2[$index]."");

或

else {print "Image not matching:"; print $tfiles2[$index]; last;}

请注意，无论它是否在数组边界内，您都会$index递增。您不检查条件 $index > $#tfiles ，这应该会中断循环。

您可能希望通过打印长度来断言两个输入数组都包含>> 900 个元素，例如 print "length: ", scalar @array, "n"; 。

您可以通过测试数组中元素的定义性来测试undefined错误实际发生在哪个索引：

if (not defined $tfiles[$index] or not defined $files1[$i]) {
   die "There was an undefined element at index=$index, i=$i";
}

但话又说回来，$i 和 $index 之间的偏移量是恒定的（如我的回答中所述），因此您不必实际携带两个变量。

一个简单的比较器子例程可以使代码更具可读性，从而有助于调试（请参阅过程编程）。

# return true if matching, false otherwise.
sub compare_images {
   my ($file1, $file2) = @_;
   my $image1 = Image::Magick->new;
   $image1->Read(filename => $file1);
   my $image2 = Image::Magick->new;
   $image2->Read(filename => $file2);
   my $result = $image1->Compare(image => $image2, metric => 'AE')->Get('error');
   # free memory
   undef $image1;
   undef $image2;
   return 0 == $result;
}

称为喜欢

my $image_root = "C:/dropbox/Image_Compare";
my ($folder1, $folder2) = qw(folder1 folder2);
unless (compare_images("$image_root/$folder1/$files1[$i]", 
                       "$image_root/$folder2/$tfiles[$index]")) {
   print "Images not matching at index=$index, i=$in";
   print "filename: $tfiles[$index]n";
   last;
}

您可以像阅读目录一样

sub get_images_from_dir {
   my ($dirname) = @_;
   -d $dirname or die qq(The path "$dirname" doesn't point to a directory!);
   opendir my $dir => $dirname or die qq(Can't open "$dirname": $!);
   my @files = grep {!/^./ and -f "$dirname/$_"} readdir $dir;
   closedir $dir;
   unless (@files) { die qq(There were no interesting files in "$dirname".) }
   return @files;
}

此类步骤使代码更具可读性，并易于插入检查。