请教perl语言,/(\d{4}(\-?

请教perl语言,/(\d{4}(\-?
请教perl语言,/(\d{4}(\-?

请教perl语言,/(\d{4}(\-?
这一正则在尝试寻找 连续 4 个数字,及 1 个可有可无的 - (横杠)
但值得留意的是,这里有两组 () ,在括号中能找到匹配的文字时,会顺序存到 $1,$2 ...中
$str = "1234";
$str /(\d{4}(\-?))/ ;
if ( $1 and $2 ) { print "\$1 = '$1',\$2 = '$2'.number with - " }
elsif ( $1 ) { print "\$1 = '$1',\$2 = '$2'.number only" }
else { print "not matched" }
print "$/$/";
$str = "9876-";
$str /(\d{4}(\-?))/ ;
if ( $1 and $2 ) { print "\$1 = '$1',\$2 = '$2'.number with - " }
elsif ( $1 ) { print "\$1 = '$1',\$2 = '$2'.number only" }
else { print "not matched" }