Question

我已使用Names及其类排名初始化哈希，如下所示

a=>5,b=>2,c=>1,d=>3,e=>5

到目前为止我已经有了这段代码

my %Ranks = reverse %Class;     #As I need to find out who's ranked first
print "\nFirst place goes to.... ", $Ranks{1};

代码只打印出来

"First place goes to...."

我希望它打印出来

First place goes to....c

你能告诉我'我在哪里错了吗？

类哈希正确打印但如果我尝试使用

打印反向哈希

foreach $t (keys %Ranks) { 
print "\n $t $Ranks{$t}"; }

打印

5
abc23
cab2
ord

如果这有任何帮助

完整代码

#Script to read from the data file and initialize it into a hash
 my %Code;
 my %Ranks;

 #Check whether the file exists
 open(fh, "Task1.txt") or die "The File Does Not Exist!\n", $!;

while (my $line = <fh>) {   
chomp $line;
    my @fields = split /,/, $line;
    $Code{$fields[0]} = $fields[1];
    $Class{$fields[0]} = $fields[2];
} 
close(fh); 

#Prints the dataset 
print "Code \t Name\n";
foreach $code ( keys %Code) {
    print "$code \t $Code{$code}\n";
}


#Find out who comes first
my %Ranks = reverse %Class;

foreach $t (keys %Ranks)
{
    print "\n $t $Ranks{$t}";
}
print "\nFirst place goes to.... ", $Ranks{1}, "\n";

Answer 1

如果要检查数据结构实际包含的内容，请使用Data :: Dumper。 use Data::Dumper; local $Data::Dumper::Useqq = 1; print(Dumper(\%Class));。你会找到非chomp ed换行符。

Answer 2

您需要使用chomp。目前，您的$fields[2]值有一个尾随换行符。

将文件读取循环更改为此

while (my $line = <fh>) {       
  chomp $line;
  my @fields = split /,/, $line;
  $Code{$fields[0]} = $fields[1];
  $Class{$fields[0]} = $fields[2];
}

无法从散列反转中检索值（Perl）

2 个答案: