什么是Perl相当于PHP的print_r()？

Question

我发现PHP中的print_r非常有用,但想知道在Perl中是否有任何远程等效的东西？

Answer 1

注意@tchrist建议Data :: Dump over Data :: Dumper.我不知道它,但从它的外观来看,似乎它更容易使用,产生更好看,更容易解释结果.

Data :: Dumper:

以上链接中显示的示例片段.

use Data::Dumper;

package Foo;
sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};

package Fuz;                       # a weird REF-REF-SCALAR object
sub new {bless \($_ = \ 'fu\'z'), $_[0]};

package main;
$foo = Foo->new;
$fuz = Fuz->new;
$boo = [ 1, [], "abcd", \*foo,
         {1 => 'a', 023 => 'b', 0x45 => 'c'}, 
         \\"p\q\'r", $foo, $fuz];

########
# simple usage
########

$bar = eval(Dumper($boo));
print($@) if $@;
print Dumper($boo), Dumper($bar);  # pretty print (no array indices)

$Data::Dumper::Terse = 1;          # don't output names where feasible
$Data::Dumper::Indent = 0;         # turn off all pretty print
print Dumper($boo), "\n";

$Data::Dumper::Indent = 1;         # mild pretty print
print Dumper($boo);

$Data::Dumper::Indent = 3;         # pretty print with array indices
print Dumper($boo);

$Data::Dumper::Useqq = 1;          # print strings in double quotes
print Dumper($boo);

Answer 2

与Perl一样,您可能更喜欢古老的Data :: Dumper的替代解决方案:

• Data :: Dump :: Streamer的输出比Data :: Dumper高,并且还可以比Data :: Dumper更好地序列化一些数据,
• YAML(或Yaml :: Syck,或其他YAML模块)在YAML中生成数据,这是非常清晰的.

当然,使用调试器,您可以使用'x'命令显示任何变量.我特别喜欢表单' x 2 $complex_structure',其中2(或任何数字)告诉调试器只显示2级嵌套数据.

Answer 3

Data :: Dumper的替代方法是不生成有效的Perl代码,而是更易于浏览的格式(与xPerl调试器的命令相同)是Dumpvalue.它也消耗了更少的内存.

同样,还有Data :: Dump :: Streamer,它在各种边缘和角落情况下比Data :: Dumper更准确.