Perl – 将文件从文件加载到哈希

发布时间：2020-12-16 06:16:53 所属栏目：大数据来源：网络整理

导读：是否可以将文件中的记录直接加载到哈希中？记录以/ begin和/ end分隔,并具有固定的内容顺序. 我想要的是这样的哈希填充： hash_city{London}{slurped_record}='/begin CITY Londonn bign Englandn Sterlingn/end CITY'hash_city{Paris}{slurped_record}=

是否可以将文件中的记录直接加载到哈希中？记录以/ begin和/ end分隔,并具有固定的内容顺序.

我想要的是这样的哈希填充：

hash_city{London}{slurped_record}='/begin CITY Londonn   bign   Englandn   Sterlingn/end CITY'
hash_city{Paris}{slurped_record}='/begin CITYn   Parisn   bign   Francen   Euron/end CITY'
hash_city{Melbourne}{slurped_record}='/begin CITYnn   Melbournen   bign   Australian   Dollarn   hotn/end CITY'

然后我可以关闭并处理哈希等中的记录.(‘slurped_record’条目的原因是后来我想添加新密钥来说伦敦像’country = England’等

hash_city{London}{Country}='England'

我已经设法通过啜饮而不是逐行读取文件来实现某些功能.匹配/ begin,构建记录($rec.= $_),然后匹配/ end和处理.它有点乱,想知道是否有更优雅的Perl方法..

到目前为止我的代码尝试如下：

use strict;
use warnings;
use Data::Dumper;

my $string = do {local $/; <DATA>};
my %hash_city = map{$2=>$1} $string =~ /(/begins+CITYs+(w+).+/ends+CITY)/smg;
print Dumper(%hash_city);

__DATA__
stuff
stuff
/begin CITY London
   big
   England
   Sterling
/end CITY

stuff
stuff

/begin CITY
   Paris
   big
   France
   Euro
/end CITY
stuff

/begin CITY

   Melbourne
   big
   Australia
   Dollar
   hot
/end CITY

stuff

解决方法

做了一个小程序来展示相反的方式,推进你的过程. )不知道是不是优雅与否,但我认为它完成了工作. )

my %city_record;

## we're going to process the input file in chunks.
## here we define the chunk start marker,and make Perl to separate file input with it
local $/ = "/begin CITY";

# ignoring anything before the first section starts
scalar <DATA>;

while (<DATA>) {
  # throwing out anything after the section end marker
  # (might be done with substr-index combo as well,# but regex way was shorter and,for me,more readable as well )
  my ($section_body) = m{^(.+)/end CITY}ms;

  # now we're free to parse the section_body as we want. 
  # showing here pulling city name - and the remaining data,by using the split special case
  my ($city,@city_data) = split ' ',$section_body;

  # filling out all the fields at once
  # (may seem a bit unusual,but it's a simple hash slice actually,great Perl idiom)
  @{ $city_record{$city} }{qw/ size country currency misc /} = @city_data;
}

# just to test,use something of yours instead. )
print Dumper %city_record;

（编辑：李大同）

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