变量之间的 Perl 混淆

Question

我有以下代码

my $content = $response->content;
$content =~ /username=([\s\S]+?)&/;
my $username = $1;
print $username; #Prints the text

假设我想再做一次，但针对不同的文本

例如

$content =~ /rank=([\s\S]+?)&/;
my $rank = $1;
print $rank; #Prints the username text

我必须将 $1 换成其他东西吗？

Answer 1

my $content = $response->content;
$content =~ /username=([\s\S]+?)&/;
my $username = $1;
print $username; #Prints the text

$content =~ /rank=([\s\S]+?)&/;

#if the above regex does not match, $1 remains set to the previous $1

my $rank = $1;
print $rank; #Prints the username text

这样会更安全:

if ($content =~ /rank=([\s\S]+?)&/){
    my $rank = $1;
}

或者，更优雅地:

my ($rank) = $content =~ /rank=([\s\S]+?)&/;
print "\n rank:$rank" if defined $rank; #Prints the username text