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arrays - 创建包含多个变量的 JSON 数组

问题描述

我想修改我的 Perl 脚本以使用json_encode函数输出变量列表，但我不确定如何。

这是我未修改的 Perl 脚本的输出：

Vicia_sativa = Vicia_sativa.png 
Geranium_maculatum = Geranium_maculatum.png 
Narcissus_pseudonarcissus = Narcissus_pseudonarcissus1.png Narcissus_pseudonarcissus2.png 
Polygonum_persicaria = Polygonum_persicaria1.png Polygonum_persicaria2.png 
Corylus_americana = Corylus_americana1.png Corylus_americana2.png

等号左边的变量是植物名称，等号右边的一个或多个文件名是植物照片。请注意，这些文件名没有用逗号分隔。

这是生成上述输出的 Perl 脚本：

#!/usr/bin/perl
use strict;
use warnings;
use English;   ## use names rather than symbols for special variables

my $dir = '/Users/jdm/Desktop/xampp/htdocs/cnc/images/plants';

opendir my $dfh, $dir  or die "Can't open $dir: $OS_ERROR";
my %genus_species;  ## store matching entries in a hash

for my $file (readdir $dfh)
{
    next unless $file =~ /.png$/;  ## entry must have .png extension
    my $genus = $file =~ s/\d*\.png$//r;
    push(@{$genus_species{$genus}}, $file);   ## push to array,the @{} is to cast the single entry to a reference to an list
}

for my $genus (keys %genus_species)
{
    print "$genus = ";
    print "$_ " for sort @{$genus_species{$genus}}; # sort and loop though entries in list reference
    print "\n";
}

请告知如何在JSON数组中输出这些变量。谢谢。

更新...这是修订后的脚本，其中包含每个论坛成员的建议更改：

#!/usr/bin/perl
use strict;
use warnings;

use JSON::PP;

use English;   ## use names rather than symbols for special variables

my $dir = '/Users/jdm/Desktop/xampp/htdocs/cnc/images/plants';

opendir my $dfh, $dir  or die "Can't open $dir: $OS_ERROR";
my %genus_species;  ## store matching entries in a hash

for my $file (readdir $dfh)
{
    next unless $file =~ /.png$/;  ## entry must have .png extension
    my $genus = $file =~ s/\d*\.png$//r;
    push(@{$genus_species{$genus}}, $file);   ## push to array,the @{} is to cast the single entry to a reference to an list
}

print(encode_json(\%genus_species));

这个修改后的代码有效！但是，文件名不再排序。任何想法如何将排序合并到encode_json函数中？

标签： arraysjsonperl

解决方案

实际上非常简单......您可以使用JSON::PP 模块并将哈希的引用传递给encode_json().

#!/usr/bin/perl

use strict;
use warnings;

use JSON::PP;
# your other code goes here...

# instead of `for my $genus (keys %genus_species) { ... }` do:
print(encode_json(\%genus_species));

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