perl中访问散列的键对应的值时候键到底需不需要引号括起来?

[root@node254 ~]# perl
%student = ( "Math" => {"joe" => 95,"peter"=> 100},
             "Science" => {"joe"=> 100,"peter" =>80 }
             );
print "on the Math test joe got ";
print "$student{Math}->{joe}.\n";
__END__
on the Math test joe got 95.


[root@node254 ~]# perl
%student = ( "Math" => {"joe" => 95,"peter"=> 100},
             "Science" => {"joe"=> 100,"peter" =>80 }
             );
print "on the Math test joe got ";
print "$student{'Math'}->{'joe'}.\n";
__END__
on the Math test joe got 95.

[root@node254 ~]# perl
%student = ( "Math" => {"joe" => 95,"peter"=> 100},
             "Science" => {"joe"=> 100,"peter" =>80 }
             );
print "on the Math test joe got ";
print "$student{\"Math\"}->{\"joe\"}.\n";
__END__
on the Math test joe got 95.


在上面的例子中键有没有引号好象都可以呀,请大侠解惑

[root@node254 ~]# perl -v

This is perl, v5.10.1 (*) built for x86_64-linux-thread-multi

回复 aoma


    看到老外有说到这句话: It is not necessary to quote the key if it is a single word
是不是说如里{}里的键是一个词(我觉得是一个字符串的话)就不用引号括起来的意思