perl – 如何解析文件,创建记录并对记录执行操作,包括术语频率和距离计算

该计划的要求如下：

>提示三个命令之一：频率,长度,密度d(d是某个数字)：

我正在寻找下面代码中我写的(并且需要写)的反馈.我特别感谢有关如何编写我的潜艇的任何反馈.我在底部包含了示例输入数据.

我看到的程序结构和功能描述：

$^W = 1; # turn on warnings
use Strict; # behave!

my @fields;
my @recs;

while ( <DATA> ) {
 chomp;
 @fields = split(/\s+/);
 push @recs,makeRecord(@fields);
}

for (my $i = 0; $i < @recs; $i++) {
 printRec( $recs[$i] );
}
    my %command_table = (
 freq => \&freq,length => \&length,density => \&density,Help => \&Help,quit => \&quit
 );

print "Enter a command: ";
while ( <STDIN> ) {
 chomp; 
 my @line = split( /\s+/);
 my $command = shift @line;
 if ($command !~ /^freq$|^density$|length|^Help$|^quit$/ ) {
    print "Command must be: freq,length,density or quit\n";
    }
  else {
    $command_table{$commanD}->();
    }
 print "Enter a command: ";
 }

sub makeRecord 
    # Read the entire line and make records from the lines that contain the 
    # word ATOM or HETATM in the first column. Not sure how to do this:
{
 my %record = 
 (
 serialnumber => shift,aminoacid => shift,coordinates => shift,element  => [ @_ ]
 );
 return\%record;
}

sub freq
    # take an array of atom records,return a hash whose keys are 
    # disTinct atom names and whose values are the frequences of
    # these atoms in the array.  

sub length
    # take an array of atom records and return the max distance 
    # between all pairs of atoms in that array. My instructor
    # advised this would be constructed as a for loop inside a for loop. 

sub density
    # take an array of atom records and a number d and will return a
    # hash whose keys are atom serial numbers and whose values are 
    # the number of atoms within that distance from the atom with that
    # serial number. 

sub Help
{
    print "To use this program,type either\n","freq\n","length\n","density followed by a number,d,\n","Help\n","quit\n";
}

sub quit
{
 exit 0;
}

# truncaTing for tesTing purposes. Actual data is aprox. 100 columns 
# and starts with ATOM or HETATm.
__DATA__
ATOM   4743  CG  GLN A 704      19.896  32.017  54.717  1.00 66.44           C  
ATOM   4744  CD  GLN A 704      19.589  30.757  55.525  1.00 73.28           C  
ATOM   4745  OE1 GLN A 704      18.801  29.892  55.098  1.00 75.91           O