Question

我有一个Perl脚本来逐行分析许多兆字节的数据。

作为一个例子，我将在几天之前使用道琼斯平均指数的收盘价。

读取数据并且文件中的数据布局很简单。在这个例子中，它是：

Date Open High Low Close Volume Adj-Close

当我读取数据时，会执行许多计算。保留一些数据和计算以供以后使用。假设新数据是：

Date Open Adj-Close %change [more data to be added]

以下是一些示例代码：

use warnings; use strict;

my @trades;

while(<DATA>) {
    chomp;
 my ($year,$mon,$day,$open,$high,$low,$close,$vol,$ad_close);

 if(($year,$mon,$day,$open,$high,$low,$close,$vol,$ad_close)=
   /^(\d+)-(\d+)-(\d+),    #date YYYY-MM-DD
   (\d+\.\d+),             #open
   (\d+\.\d+),             #High
   (\d+\.\d+),             #Low
   (\d+\.\d+),    #Close
   (\d+),     #Vol
   (\d+\.\d+)/x)    #adj cl
    {
    my $drp=($ad_close-$open)/$open;
# HERE Created:    
    push @trades, [$year,$mon,$day,$open,$ad_close,$drp];     
   }
   else {
      print "$_ does not match...\n";
   }   
}

# widely separated and in multiple places... 

foreach my $trade_ref (@trades) {
#HERE Referenced
 my ($year,$mon,$day,$open,$ad_close,$drp)=@$trade_ref;

 print "$year-$mon-$day $open,$ad_close,$drp\n";          
}

# Dow Jones data by day...
__DATA__
2010-10-08,10948.50,11055.29,10901.12,11006.48,3871420000,11006.48
2010-10-07,10968.41,11032.17,10878.04,10948.58,3910550000,10948.58
2010-10-06,10936.79,11015.86,10880.08,10967.65,4073160000,10967.65
2010-10-05,10752.63,10982.98,10752.63,10944.72,4068840000,10944.72
2010-10-04,10828.85,10875.54,10682.66,10751.27,3604110000,10751.27
2010-10-01,10789.72,10907.41,10759.14,10829.68,4298910000,10829.68
2010-09-30,10835.96,10960.99,10732.27,10788.05,4284160000,10788.05
2010-09-29,10857.98,10901.96,10759.75,10835.28,3990280000,10835.28
2010-09-28,10809.85,10905.44,10714.03,10858.14,4025840000,10858.14
2010-09-27,10860.03,10902.52,10776.44,10812.04,3587860000,10812.04
2010-09-24,10664.39,10897.83,10664.39,10860.26,4123950000,10860.26
2010-09-23,10738.48,10779.65,10610.12,10662.42,3847850000,10662.42
2010-09-22,10761.11,10829.75,10682.40,10739.31,3911070000,10739.31
2010-09-21,10753.39,10844.89,10674.83,10761.03,4175660000,10761.03
2010-09-20,10608.08,10783.51,10594.38,10753.62,3364080000,10753.62
2010-09-17,10595.44,10689.29,10529.67,10607.85,4086140000,10607.85
2010-09-16,10571.75,10624.58,10499.43,10594.83,3364080000,10594.83
2010-09-15,10526.42,10609.21,10453.15,10572.73,3369840000,10572.73
2010-09-14,10544.81,10622.69,10460.34,10526.49,4521050000,10526.49
2010-09-13,10458.60,10605.73,10458.45,10544.13,4521050000,10544.13
2010-09-10,10415.01,10502.80,10376.34,10462.77,3061160000,10462.77
2010-09-09,10388.22,10515.86,10359.23,10415.24,3387770000,10415.24
2010-09-08,10338.57,10460.50,10318.93,10387.01,3224640000,10387.01
2010-09-07,10446.80,10448.99,10304.44,10340.69,3107380000,10340.69
2010-09-03,10321.92,10484.71,10321.92,10447.93,3534500000,10447.93
2010-09-02,10270.08,10350.98,10211.80,10320.10,3704210000,10320.10
2010-09-01,10016.01,10305.87,10016.01,10269.47,4396880000,10269.47
2010-08-31,10006.42,10101.53,9915.73,10014.72,4038770000,10014.72

在标记为#HERE的代码中的位置，请注意我首先将匿名数组推送到另一个命名数组以供以后访问。稍后（在实际程序的后面），我通过引用访问相同的数组。

到目前为止，我刚刚从第一个＃HERE剪切了“模板”[$year,$mon,$day,$open,$ad_close,$drp]的文本，并手动将my ($year,$mon,$day,$open,$ad_close,$drp)=@$trade_ref;粘贴到程序中的另一个＃HERE中。必须是一个更好的方式...

有没有办法让我可以拥有一个我推送的匿名数组的模板，以便在其他情况下通过脚本自动地以有序的方式引用它？在真实的脚本中，分析的结果如$drp发生变化，我想要改变数据的创建，即使我不改变my ($year,$mon,$day,$open,$ad_close,$drp)=@$trade_ref;如果这是一个C程序，定义可以是单个地方的宏......

我正在考虑推送一个匿名哈希而不是一个数组，其中哈希的名称/值对具有该值的名称，然后是该值的值。从理论上讲，我知道这会起作用，但让我感到浪费和缓慢。实际数据集中大约有2 GB的数据，我可以使用当前设计快速完成。

有更好的方法吗？

Answer 1

Hashrefs可能没有您想象的那么慢或浪费。
POE方法：
use constant (YEAR => 0, MON => 1, DAY => 2, ...);
$trade_ref->[YEAR]等。

Answer 2

use strict; use warnings;
use constant {
    YEAR => 0, MON      => 1, DAY => 2,
    OPEN => 3, AD_CLOSE => 4, DRP => 5,
};

my @trades;
while(<DATA>) {
    chomp;
    my $dow = parse_dow( $_ );
    push @trades, $dow if @$dow;
}

print "@{$_}[YEAR, MON, DAY, OPEN, AD_CLOSE, DRP]\n"
for @trades;

sub parse_dow {
    my ($dow) = @_;

    my ($date, $open, $high, $low, $close, $vol, $ad_close)
    = split /,/, $dow;        
    my ($year, $mon, $day) = split /-/, $date;
    my $drp = ( $ad_close - $open ) / $open;

    return [$year, $mon, $day, $open, $ad_close, $drp];
}

__DATA__
2010-10-08,10948.50,11055.29,10901.12,11006.48,3871420000,11006.48
2010-10-07,10968.41,11032.17,10878.04,10948.58,3910550000,10948.58
2010-10-06,10936.79,11015.86,10880.08,10967.65,4073160000,10967.65

Answer 3

祝福阵列的负载不会比未祝福的阵列多得多。

package Trade;
use strict;
use warnings;
use English qw<@LAST_MATCH_START @LAST_MATCH_END>;

my @slots = qw<year month day open high low close vol ad_close drop>;
my %slot_for
    = (( map { $slots[$_] => $_ } 0..$#slots )
      , ( map { $_ => -1 } qw<date> )
      )
    ;

foreach my $i ( 0..$#slots ) {
    my $name = $slots[$i];
    no strict 'refs';
    *$name = sub {
        my ( $self, $value ) = @_;
        my $slotr = \$self->[$i];
        return $$slotr unless $#_;
        my $old = $$slotr;
        $$slotr = $value;
        return $$slotr;
    };
}

my @trades;
my %format_for;

sub trades { return @{[ @trades ]} };

sub new {
    my $class = shift;
    my @args  = @_;

    if ( @args == 0 ) {
        $args[0] = $_;
    }
    if ( @args == 1 ) {
        my $line = shift @args;
        @args
            = $line =~
              m/^(\d+)-(\d+)-(\d+), #date YYYY-MM-DD
                 (\d+\.\d+),        #open
                 (\d+\.\d+),        #High
                 (\d+\.\d+),        #Low
                 (\d+\.\d+),        #Close
                 (\d+),             #Vol
                 (\d+\.\d+)
              /x
            ;
        my ( $open, $ad_close ) = @args[3,8];
        push @args, ( $ad_close - $open ) / $open;
    }

    my $self = bless \@args, $class;
    push @trades, $self;
    return $self;
}

sub format {
    my $self   = shift;
    my $format = shift;
    my $format_ref = $format_for{ $format };
    unless ( $format_ref ) {
        my @format_list;
        my $fmt = $format;
        while ( $fmt =~ m/\$(\w+)/g ) {
            next unless exists $slot_for{ $1 };
            push @format_list, \&$1;
            substr( $fmt, $LAST_MATCH_START[0], $LAST_MATCH_END[0] - $LAST_MATCH_START[0], '%s' );
            pos( $fmt ) = $LAST_MATCH_START[0] + 2;
        }
        $fmt =~ s/\\n/\n/gm;
        $format_ref
            = $format_for{ $format }
            = { format => $fmt, list => \@format_list }
            ;
    }
    return $format unless $format_ref->{list};
    my ( $fmt, $format_list ) = @$format_ref{ qw<format list> };
    return sprintf( $fmt, map { $_->( $self ) } @$format_list );
}

sub date {
    my $str = join( '-', &year, &month, &day );
    return $str;
}

package main;

Trade->new while <DATA>;

print $_->format( '$date $open,$ad_close,$drop\n' ) foreach Trade->trades();
__DATA__
2010-10-08,10948.50,11055.29,10901.12,11006.48,3871420000,11006.48
2010-10-07,10968.41,11032.17,10878.04,10948.58,3910550000,10948.58
2010-10-06,10936.79,11015.86,10880.08,10967.65,4073160000,10967.65
2010-10-05,10752.63,10982.98,10752.63,10944.72,4068840000,10944.72
2010-10-04,10828.85,10875.54,10682.66,10751.27,3604110000,10751.27
2010-10-01,10789.72,10907.41,10759.14,10829.68,4298910000,10829.68
2010-09-30,10835.96,10960.99,10732.27,10788.05,4284160000,10788.05
2010-09-29,10857.98,10901.96,10759.75,10835.28,3990280000,10835.28
2010-09-28,10809.85,10905.44,10714.03,10858.14,4025840000,10858.14
2010-09-27,10860.03,10902.52,10776.44,10812.04,3587860000,10812.04
2010-09-24,10664.39,10897.83,10664.39,10860.26,4123950000,10860.26
2010-09-23,10738.48,10779.65,10610.12,10662.42,3847850000,10662.42
2010-09-22,10761.11,10829.75,10682.40,10739.31,3911070000,10739.31
2010-09-21,10753.39,10844.89,10674.83,10761.03,4175660000,10761.03
2010-09-20,10608.08,10783.51,10594.38,10753.62,3364080000,10753.62
2010-09-17,10595.44,10689.29,10529.67,10607.85,4086140000,10607.85
2010-09-16,10571.75,10624.58,10499.43,10594.83,3364080000,10594.83
2010-09-15,10526.42,10609.21,10453.15,10572.73,3369840000,10572.73
2010-09-14,10544.81,10622.69,10460.34,10526.49,4521050000,10526.49
2010-09-13,10458.60,10605.73,10458.45,10544.13,4521050000,10544.13
2010-09-10,10415.01,10502.80,10376.34,10462.77,3061160000,10462.77
2010-09-09,10388.22,10515.86,10359.23,10415.24,3387770000,10415.24
2010-09-08,10338.57,10460.50,10318.93,10387.01,3224640000,10387.01
2010-09-07,10446.80,10448.99,10304.44,10340.69,3107380000,10340.69
2010-09-03,10321.92,10484.71,10321.92,10447.93,3534500000,10447.93
2010-09-02,10270.08,10350.98,10211.80,10320.10,3704210000,10320.10
2010-09-01,10016.01,10305.87,10016.01,10269.47,4396880000,10269.47
2010-08-31,10006.42,10101.53,9915.73,10014.72,4038770000,10014.72

Answer 4

也许值得研究一下你是否可以在一个有福的数组引用中隐藏数组的内容。有一个交易类，将数组对象推送到你的@trades数组，然后有一个方法来返回数据和价格将隐藏你的代码重复的一些问题，但由于该方法的风险，运行时间稍慢调用。使用命名常量直接调用数组会更快，我认为这比其他任何东西都重要。

Perl：匿名数组的模板？

4 个答案: