Question

我有两个数组，一个包含搜索词，另一个是从文件中提取的多行。我有一个嵌套的foreach语句，正在搜索所有组合，但只有最后一个匹配项显示出来，尽管我知道还有许多其他匹配项！！我尝试了许多不同版本的代码，但这是我的最后一个版本：

open (MYFILE,  searchTerms.txt );
open (MYFILE2,  fileToSearchIn.xml );

@searchTerms = <MYFILE>;
@xml = <MYFILE2>;

close(MYFILE2);
close(MYFILE);
$results = "";

foreach $searchIn (@xml)
{
    foreach $searchFor (@searchTerms)
    {
        #print "searching for $searchFor in: $searchIn
";
        if ($searchIn =~ m/$searchFor/)
        {
            $temp = "found in $searchIn 
 while searching for: $searchFor ";
            $results = $results.$temp."
";
            $temp = "";
        }
    }
}

print $results;

Answer 1

你应该在程序开始时始终使用严格的和使用警告my.声明所有变量。这尤其适用于您请求代码帮助的情况，因为此措施可以快速发现许多简单的错误。

As Raze2dust has said it is important to remember that lines read from a file will have a trailing newline " " character. If you were checking for exact matches between a pair of lines then this wouldn t matter, but since it s not working for you I assume the strings in searchTerms.txt can appear anywhere in the lines of fileToSearchIn.xml. That means you need to use chomp the strings from searchTerms.txt; lines from the other file can stay as they are.

通过使用文件：：Slurp模块。它为您完成所有的文件处理，如果您要求，它将从输入文本中抓取任何换行符。

我已经将你的程序更改为使用此模块，这样你就可以看到它是如何工作的。

use strict;
use warnings;

use File::Slurp;

my @searchTerms = read_file( searchTerms.txt , chomp => 1);
my @xml = read_file( fileToSearchIn.xml );

my @results;

foreach my $searchIn (@xml) {
  foreach my $searchFor (@searchTerms) {
    if ($searchIn =~ m/$searchFor/) {
      push @results, qq/Found in "$searchIn"
 while searching for "$searchFor"/;
    }
  }
}

print "$_
" for @results;

Answer 2

chomp您的输入以删除换行符：

open (MYFILE,  searchTerms.txt );
open (MYFILE2,  fileToSearchIn.xml );

@searchTerms = <MYFILE>;
@xml = <MYFILE2>;

close(MYFILE2);
close(MYFILE);
$results = "";

foreach $searchIn (@xml)
{
    chomp($searchIn);
    foreach $searchFor (@searchTerms)
    {
        chomp($searchFor);
        #print "searching for $searchFor in: $searchIn
";
        if ($searchIn =~ m/$searchFor/)
        {
            $temp = "found in $searchIn 
 while searching for: $searchFor ";
            $results = $results.$temp."
";
            $temp = "";
        }
    }
}

print $results;

Basically, you are thinking you are searching for a , but actually it is searching for a because that is how it reads the input unless you use chomp. It matches only if a is the last character because in that case, it will be succeeded by a newline.

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