在perl中读取文件时哈希不能正确打印

Question

我试图通过读取文件在perl中建立一个哈希。文件内容如下:

s1=i1
s2=i2
s3=i3

我的代码如下:

my $FD;
open ($FD, "read") || die "Cant open the file: $!";
while(<$FD>){
    chomp $_;
    print "n Line read = $_n";
    $_ =~ /([0-9a-z]*)=([0-9a-zA-Z]*)/;
    @temp_arr=($2,$3,$4);
    print "Array = @temp_arrn";
    $HASH{$1}=@temp_arr;
    print "Hash now = ";
    foreach(keys %HASH){print "$_ = $HASH{$_}->[0]n";};

}

我的输出如下

 Line read = s1=i1
Array = i1
Hash now = s1 = i1
 Line read = s2=i2
Array = i2
Hash now = s2 = i2
s1 = i2
 Line read = s3=i3
Array = i3
Hash now = s2 = i3
s1 = i3
s3 = i3

为什么最后所有键的值都打印为i3?????

Answer 1

因为每个值都引用了同一个数组

试试这样写:

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
my %result;
open my $fh, '<', 'read' or die $!;
while (my $line=<$fh>) {
    chomp $line;
    my ($key, $value)=split /=/, $line, 2;
    die "$key already exists" if (exists $result{$key});
    $result{$key}=$value;
}
print Dumper(%result);

输出是:

$VAR1 = {
          's1' => 'i1',
          's3' => 'i3',
          's2' => 'i2'
        };

Answer 2

@temp_arr是对全局变量@temp_arr的引用。你反复地重新初始化它，但它仍然是对原始变量的引用。

您需要在词法上限定@temp_arr (my @temp_arr=($2,$3,$4);)的作用域，或者传递一个新的引用到散列($HASH{$1} = [ $2,$3,$4 ];)

Answer 3

试试这个:

my $FD;
open ($FD, "read") || die "Cant open the file: $!";
for(<$FD>){
   chomp $_;
   push(@temp_arr,$1,$2) if($_=~/(.*?)=(.*)/);
}
%HASH=@temp_arr;
print Dumper %HASH;

Answer 4

试试这个

open (my $FD, "read") || die "Cant open the file: $!";
my %HASH = map {chomp $_; my @x = split /=/, $_; $x[0] => $x[1]} <$FD>;
print "Key: $_ Value: $HASH{$_}n" for (sort keys %HASH);

Answer 5

除了"open"语句中的错误，尽量保持简单，然后使其不可读。

my ($FD, $a, $b, $k);
$FD = "D:\Perl\test.txt";
open (FD, "<$FD") or die "Cant open the file $FD: $!";
while(<FD>){
    chomp $_;
    print "n Line read = $_n";
    ($a, $b) = split('=', $_);
    print "A: $a, B: $bn";
    $HASH{$a}="$b";
    print "Hash now ..n";
    foreach $k (sort keys %HASH){
        print "Key: $k -- HASH{$k} = $HASH{$k}n";
    }
}