[问题]谁能解释一下这段话？

5451vs5451 · #1

As with regular pattern matching, any capturing parentheses that are not matched
in a "split()" will be set to "undef" when returned:
@fields = split /(A)│B/, "1A2B3";
# @fields is (1, ’A’, 2, undef, 3)

xki · #2

如果是 ……

代码：全选

@list = split/A/,"1A2A3A4A";
foreach (@list){
print "[",$_,"].";
}

输出结果就是：[1].[2].[3].[4].

如果是 ……

代码：全选

@list = split/(A)/,"1A2A3A4A";
foreach (@list){
print "[",$_,"].";
}

输出结果就是：[1].[A].[2].[A].[3].[A].[4].[A].

可以理解为：括号对字符起到了“保留而不替换”的作用

5451vs5451 · #3

假如有

代码：全选

$string="f1 (abc), f2, f3 (def); f4";

怎样才能把它拆成

代码：全选

@field=qw{f1 f2 f3 f4};

呢？

xki · #4

代码：全选

#!/usr/bin/perl
my($str,@array);
$str="f1 (abc), f2, f3 (def); f4";
while ($str=~/(f\d)/g){
	push @array,$1;
}
print "@array";