Perl 中是否有内置的“hash to string”？
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Is there a builtin "hash to string" in Perl?
提问by cdleary
I'm coming to learn Perl from a Python background where the following hash-to-string conversion is built in to the language:
我即将从 Python 背景中学习 Perl，其中语言内置了以下哈希到字符串的转换：
>>> d = {'a': 1, 'b': 2, 'c': 3}
>>> str(d)
"{'a': 1, 'c': 3, 'b': 2}"
Is there a builtin and/or module that has a subroutine with output along the lines of:
是否有一个内置和/或模块具有一个带有以下行输出的子例程：
"('a' => 1, 'b' => 2, 'c' => 3)"
Strangely, a web search for perl "hash to string"doesn't turn up anything along the lines I'm looking for. Thanks!
奇怪的是，网络搜索perl "hash to string"并没有找到我正在寻找的任何东西。谢谢！
回答by Leon Timmermans
use Data::Dumper;
local $Data::Dumper::Terse = 1;
my $str = Dumper({a => 1, b => 2, c => 3});
回答by dwarring
回答by Greg Hewgill
There is the Data::Dumpermodule which one way to do this sort of transformation.
有一个Data::Dumper模块可以通过哪种方式进行这种转换。
回答by j_random_hacker
Use Data::Dumpinstead of Data::Dumper. It's basically the same, except without that annoying $VAR1 = ...cruft:
使用Data::Dump而不是 Data::Dumper。它基本上是一样的，除了没有那些烦人的$VAR1 = ...杂物：
use Data::Dump "pp";
print pp({a => 1, b => 2, c => 3});
Produces:
产生：
{ a => 1, b => 2, c => 3 }
If you're on Windows, Data::Dump has come pre-installed with ActivePerlsince version 5.8.
如果您使用的是 Windows，Data::Dump从 5.8 版开始就预装在ActivePerl 中。
回答by Hynek -Pichi- Vychodil
Yet Another Swallow Solution:
另一个燕子解决方案：
sub pp {
my $h = shift();
qq[{${\(join',',map"$_=>$h->{$_}",keys%$h)}}]
}
print pp({a => 1, b => 2, c => 3});
But use Data::Dumperinstead.
而是Data::Dumper改用。
For very fancy output you can use also:
对于非常花哨的输出，您还可以使用：
use Data::Dumper;
use Perl::Tidy;
sub pp {
local $Data::Dumper::Terse = 1;
local $Data::Dumper::Indent = 0;
my $source = Dumper(@_);
my $result;
Perl::Tidy::perltidy(
source => $source,
destination => $result,
argv => [qw(-pbp -nst)]
);
return $result;
}
If you prefer some keys should be first than you can use this approach (i want typefirst and positionsecond):
如果你更喜欢一些键应该是第一个，而不是你可以使用这种方法（我想要type第一个和position第二个）：
local $Data::Dumper::Sortkeys = sub {
[ sort {
if ( $b eq 'type' ) {1}
elsif ( $a eq 'type' ) {-1}
elsif ( $b eq 'position' ) {1}
elsif ( $a eq 'position' ) {-1}
else { $a cmp $b }
} keys %{ $_[0] }
];
};
回答by kamelkev
Several of the above solutions have a problem if you have the potential for multi-level structures.
如果您具有多级结构的潜力，上述几种解决方案都会出现问题。
Specifically this flag:
特别是这个标志：
$Data::Dumper::Terse = 1;
As noted on the perldoc page for Data::Dumper, the "terse" flag could generate non-perl parseable output.
如 Data::Dumper 的 perldoc 页面所述，“简洁”标志可以生成非 perl 可解析的输出。
If you possibly are going to have multi-depth structures the proper thing to do would be to instead use:
如果您可能要拥有多深度结构，那么正确的做法是改为使用：
$Data::Dumper::Indent = 0;
Which is guaranteed to be perl parseable by eval, which makes for a very very easy way of doing serialization to plaintext...
这保证可以通过 eval 进行 perl 解析，这为将序列化为纯文本提供了一种非常简单的方法......
