Perl 变量不会保持设置，即使设置为 "our"

Question

我有一个文件，我希望搜索字符串，与存储在数组中的项目相匹配。我打开文件，遍历它，当我找到我要找的东西时，我更改了一个变量标志，以便可以完成其他工作。我遇到的问题是我设置的变量没有保留。我将变量放在 foreach 循环中，使其成为 our 变量，但无济于事。

有问题的代码：

my $zed = 0;
foreach my $SUB (@sub) {
    print "We are currently looking for $SUB<br><br>";

    open (my $input, "<", "C:\Users\scottbro\Desktop\PMS.txt")
        or die "Cannot open PMS.txt: $!";

    our $flag = 0;
    ##SET Zed to keep track of where we are
    print "Zed is $zed<br>Flag is $flag<br>";
    $zed++;

    while (<$input>) {

        print "inside the while loop, flag is now $flag<br>";
        ##  IF you find what you are looking for, set flag to 1
        if (/$SUB/) {
            $flag = 1;
            print "Found sub property, flag is now $flag<br>";
            ## IF flag is 1, and line has email address, show it!
        } elsif ($flag = 1 && /<email>(.+)/) {
            print "Flag is $flag, email is <br>";
        }

    }
    close($input);
}

输出，可以看到flag变量丢失值：

We are currently looking for Property 1
Zed is 0
Flag is 0
inside the while loop, flag is now 0
inside the while loop, flag is now 
Flag is 1, email is email1
inside the while loop, flag is now 1
Flag is 1, email is email2
inside the while loop, flag is now 1
inside the while loop, flag is now 
inside the while loop, flag is now 
inside the while loop, flag is now 
Found sub property, flag is now 1
inside the while loop, flag is now 1
Flag is 1, email is email3
inside the while loop, flag is now 1
Flag is 1, email is email4
inside the while loop, flag is now 1
inside the while loop, flag is now 
inside the while loop, flag is now 
Flag is 1, email is email 5

Answer 1

你正在分配给你的测试$flag

elsif  (  $flag=1 && /<email>(.+)/ ) {  ... }

将 $flag 设置为 1 && /<email>(.+)/，如果正则表达式模式不匹配

，则为 false

应该是

if  (  $flag and /<email>(.+)/ ) { ... }

我建议你忘掉 $flag 而是使用这样的事实，即如果 $sub 没有找到，输入文件将在 eof，所以程序将无法读取无论如何

倒回文件比重新打开文件更好。几乎可以肯定数据应该被解析成哈希并直接访问，但我不能确定你提供的少量信息

my @sub;

open my $fh, '<', 'C:\Users\scottbro\Desktop\PMS.txt' or die "Cannot open PMS.txt: $!";

for my $sub ( @sub ) {

    seek $fh, 0, 0;

    while ( <$fh> ) {
        last if /$sub/;
    }

    while ( <$fh> ) {
        next unless /<email>(.+)/;
        print qq{Email for "$sub" is ""};
        last;
    }
}

Answer 2

您在测试中给 $flag 赋值，而不是检查它的值。

elsif ($flag = 1 && /<email>(.+)/)

应该是

elsif ($flag == 1 && /<email>(.+)/)

甚至更好，

elsif ($flag && /<email>(.+)/)

也就是说，重复读取同一个文件是非常低效的。这是一个没有的版本。

my $pat = join '|', map quotemeta, @subs;

my $qfn = 'C:\Users\scottbro\Desktop\PMS.txt';
open(my $fh, '<', $qfn)
   or die(qq{"Can't open "$qfn": $!\n"});

while (<$fh>) {
   my ($sub) = /($pat)/
      or next;

   defined( $_ = <$fh> )
      or last;

   my ($email) = /<email>(.+)/
      or redo;

   print(qq{Email for "$sub" is "$email"\n});
}

Perl 变量不会保持设置，即使设置为 "our"

Perl variable doesn't stay set, even when set with "our"

arrays

variables

perl

loops

global