Question

perl，一个简单的哈希

程序如下：
my @people = qw { fred barney fred wlima dino barney fred pebbles };
my %count ;
$count{$_}++ foreach @people;
我想打印最终$count{ "fred" }的哈希值，请问接下来该怎么写？ fred的哈希值是不是应该是3啊？

Answer 1

如果我这么写：print "$count{ "fred" }"; （在哈希前后加上双引号）程序就会报错：
Unquoted string "fred" may clash with future reserved word at ./perl.pl line 762.
String found where operator expected at ./perl.pl line 762, near "fred" }""
syntax error at ./perl.pl line 762, at EOF
Execution of ./perl.pl aborted due to compilation errors.
这是为什么啊？

那是因为你的“”里面还有“”，而perl会把第二个“和前面的”匹配，导致出错，你可以这样
print "$count{ \"fred\" }";

Answer 2

直接print $count{ "fred" }就可以

追问

谢谢。
如果我这么写：print "$count{ "fred" }"; （在哈希前后加上双引号）程序就会报错：
Unquoted string "fred" may clash with future reserved word at ./perl.pl line 762.
String found where operator expected at ./perl.pl line 762, near "fred" }""
syntax error at ./perl.pl line 762, at EOF
Execution of ./perl.pl aborted due to compilation errors.
这是为什么啊？