这不是我填充哈希的方式。为了方便阅读,这里是它的内容,键是一个固定长度的字符串:
my %country_hash = (
"001 Sample Name New Zealand" => "NEW ZEALAND",
"002 Samp2 Nam2 Zimbabwe " => "ZIMBABWE",
"003 SSS NNN Australia " => "AUSTRALIA",
"004 John Sample Philippines" => "PHILIPPINES,
);
我想根据值获取排序的键。所以我的期望:
"003 SSS NNN Australia "
"001 Sample Name New Zealand"
"004 John Sample Philippines"
"002 Samp2 Nam2 Zimbabwe "
我做了什么:
foreach my $line( sort {$country_hash{$a} <=> $country_hash{$b} or $a cmp $b} keys %country_hash ){
print "$line\n";
}
还有; (我怀疑这会排序,但无论如何)
my @sorted = sort { $country_hash{$a} <=> $country_hash{$b} } keys %country_hash;
foreach my $line(@sorted){
print "$line\n";
}
它们都没有正确排序。我希望有人可以提供帮助。
答案 0 :(得分:6)
如果您使用过 warnings
,您会被告知 <=>
是错误的运算符;它用于数值比较。改用 cmp
进行字符串比较。请参阅sort。
use warnings;
use strict;
my %country_hash = (
"001 Sample Name New Zealand" => "NEW ZEALAND",
"002 Samp2 Nam2 Zimbabwe " => "ZIMBABWE",
"003 SSS NNN Australia " => "AUSTRALIA",
"004 John Sample Philippines" => "PHILIPPINES",
);
my @sorted = sort { $country_hash{$a} cmp $country_hash{$b} } keys %country_hash;
foreach my $line(@sorted){
print "$line\n";
}
打印:
003 SSS NNN Australia
001 Sample Name New Zealand
004 John Sample Philippines
002 Samp2 Nam2 Zimbabwe
这也有效(没有额外的数组):
foreach my $line (sort {$country_hash{$a} cmp $country_hash{$b}} keys %country_hash) {
print "$line\n";
}