Perl:在复杂哈希中生成数组

编程入门行业动态更新时间:2024-10-19 02:23:38

本文介绍了Perl:在复杂哈希中生成数组的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

为了使我的数据更易于访问，我想将我的表格数据存储在复杂的散列中.当脚本循环遍历我的数据时，我正在尝试增加一个HoHoHoA".根据perldsc"中的指南:

In the quest to make my data more accessible, I want to store my tabulated data in a complex hash. I am trying to grow a 'HoHoHoA' as the script loops over my data. As per the guidelines in 'perldsc':

push @ { $hash{$column[$i]}{$date}{$hour} }, $data[$i];

脚本编译和运行没有问题，但不会向散列添加任何数据:

The script compiles and runs without a problem, but doesn't not add any data to the hash:

print $hash{"Frequency Min"}{"09/07/08"}{"15"};

即使键应该存在，也不返回任何内容.在哈希上运行存在"表明它不存在.

returns nothing even though the keys should exist. Running an 'exists' on the hash shows that it does not exist.

我正在读取的数据文件如下所示:

The data file that I am reading looks like this:

DATE TIME COLUMN1 COLUMN2 COLUMN3... 09/06/2008 06:12:56 56.23 54.23 56.35... 09/06/2008 06:42:56 56.73 55.28 54.52... 09/06/2008 07:12:56 57.31 56.79 56.41... 09/06/2008 07:42:56 58.24 57.30 58.86... . . .

我想将任何给定日期和小时的数组中每一列的值组合在一起，因此 {COLUMN}、{DATE} 和 {HOUR} 的三个哈希值.

I want to group together the values of each column in an array for any given date and hour, hence the three hashes for {COLUMN}, {DATE} and {HOUR}.

最终的结构将如下所示:

The resultant structure will look like this:

%monthData = ( "COLUMN1" => { "09/06/2008" => { "06" => [56.23,56.73...], "07" => [57.31,58.24...] } }, "COLUMN2" => { "09/06/2008" => { "06" => [54.23,55.28...], "07" => [56.79,57.30...] } }, "COLUMN3" => { "09/06/2008" => { "06" => [56.35,54.52...], "07" => [56.41,58.86...] } } );

看看我的代码:

use feature 'switch'; open DATAFILE, "<", $fileName or die "Unable to open $fileName !\n"; my %monthData; while ( my $line = <DATAFILE> ) { chomp $line; SCANROWS: given ($row) { when (0) { # PROCESS HEADERS @headers = split /\t\t|\t/, $line; } default { @current = split /\t\t|\t/, $line; my $date = $current[0]; my ($hour,$min,$sec) = split /:/, $current[1]; # TIMESTAMP FORMAT: dd/mm/yyyy\t\thh:mm:ss SCANLINE: for my $i (2 .. $#headers) { push @{ $monthData{$headers[$i]}{$date}{$hour} }, $current[$i]; } } } } close DATAFILE; foreach (@{ $monthData{"Active Power N Avg"}{"09/07/08"}{"06"} }) { $sum += $_; $count++; } $avg = $sum/$count; # $sum and $count are not initialized to begin with. print $avg; # hence $avg is also not defined.

希望我的需求足够清楚.如何将值附加到这些子哈希中的数组?

Hope my need is clear enough. How can I append values to an array inside these sub-hashes?

推荐答案

这应该适合你.

#!/usr/bin/perl use strict; use warnings; use List::Util qw/sum/; sub avg { sum(@_) / @_ } my $fileName = shift; open my $fh, "<", $fileName or die "Unable to open $fileName: $!\n"; my %monthData; chomp(my @headers = split /\t+/, <$fh>); while (<$fh>) { chomp; my %rec; @rec{@headers} = split /\t+/; my ($hour) = split /:/, $rec{TIME}, 2; for my $key (grep { not /^(DATE|TIME)$/ } keys %rec) { push @{ $monthData{$key}{$rec{DATE}}{$hour} }, $rec{$key}; } } for my $column (keys %monthData) { for my $date (keys %{ $monthData{$column} }) { for my $hour (keys %{ $monthData{$column}{$date} }) { my $avg = avg @{ $monthData{$column}{$date}{$hour} }; print "average of $column for $date $hour is $avg\n"; } } }

注意事项:

strict 和警告 pragmas
List::Util 模块获取求和函数
将数组放入标量上下文中以获取数组中的项数(在 avg 函数中)
更安全的三个参数版本的 open
词法文件句柄(而不是旧的裸字样式文件句柄)
首先在循环外读取头文件，以避免在循环内有特殊的逻辑
使用 hash slice 将文件数据放入结构化记录中立>
避免使用 split 的第三个参数分割不必要的时间立>
通过只在列表赋值中指定我们想要捕获的变量来避免无用的变量
使用 grep 防止将 DATE 和 TIME 键放入 %monthData
嵌套的 for 循环每个处理哈希中的一个级别

strict and warnings pragmas
List::Util module to get the sum function
putting an array in scalar context to get the number of items in the array (in the avg function)
the safer three argument version of open
the lexical filehandle (rather than the old bareword style filehandle)
reading the headers first outside the loop to avoid having to have special logic inside it
using a hash slice to get the file data into a structured record
avoiding splitting the time more than necessary with the third argument to split
avoiding useless variables by only specifying the variable we want to catch in the list assignment
using grep to prevent the DATE and TIME keys from being put in %monthData
the nested for loops each dealing with a level in the hash