Convert::SciEng - Convert 'numbers' with scientific postfixes

Convert-SciEng documentation Contained in the Convert-SciEng distribution.

Index

Code Index:

NAME

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Convert::SciEng - Convert 'numbers' with scientific postfixes

SYNOPSIS

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  #!/usr/local/bin/perl -w

  use strict;
  use Convert::SciEng

  my $c = Convert::SciEng->new('spice');
  my $s = Convert::SciEng->new('si');

  print "Scalar\n";
  print $c->unfix('2.34u'), "\n\n";

  print "Array\n";
  print join "\n", $c->unfix(qw( 30.6k  10x  0.03456m  123n 45o)), "\n";

  ##Note, default format is 5.5g
  print "Default format is %5.5g\n";
  print join "\n", $c->fix(qw( 35e5 0.123e-4 200e3 )), "";
  $c->format('%8.2f');
  print "Change the format is %8.2g\n";
  print join "\n", $c->fix(qw( 35e5 0.123e-4 200e3 )), "";

  print "Check out the SI conversion\n";
  print join "\n", $s->unfix(qw( 30.6K  10M  0.03456m  123n 45o)), "";

REQUIRES

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perl5.004_04 or greater, Carp

DESCRIPTION

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Convert::SciEng supplies an object for converting numbers to and from scientific notation with user-defined formatting. Three different styles of fix are supported, standard CS, SI and SPICE:

 SPICE  =    P    T    g    x    k   ''    m    u    n     p     f     a
 SI     =    P    T    G    M    K   ''    m    u    n     p     f     a
 Fix    = 1e15 1e12  1e9  1e6  1e3  1e0 1e-3 1e-6 1e-9 1e-12 1e-15 1e-18

 CS     =    P    T    G    M    K   ''
 Fix    = 2^50 2^40 2^30 2^20 2^10  2^0

Methods are supplied for creating the object and defining which fix style it will use, and defining for format of numbers as they are converted to scientific notation.

METHODS

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Creation

Convert::SciEng->new('style');

Creates and returns a new Number::SI object of the appropiate style, 'cs' or 'si' or 'spice'. The styles aren't case sensitive

$fix->format(FORMAT);

Sets the format of number converter TO fix to be FORMAT. FORMAT is any valid format to sprintf, like '%5.5g' or '%6.4e'. The default format is '%5.5g'.

Conversion

$fix->fix(0.030405); # 30.405m

Convert a number to scientific notation with fixes. Returns a string in the format given to it with the fix appended to the end. Also works with arrays, with an array of strings being returned.

$fix->unfix('12u'); # 12e-06

Convert a string from scientific notation. Returns a number in exponential format. Also works with arrays, with an array of numbers being returned.

Note, by examining the module it should be relatively easy to figure out how to create an object for any other scientific notation abbreviations. If you think it is something that might be useful to others, then email me and I'll add it to the module.

DIAGNOSTICS

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Unrecognized mode: MODE

(F) Generated when you try specify an illegal mode like so:

  $a = Convert::SciEng->new('foo');
Illegal printf format: FORMAT

(F) An illegal format was specified. Valid formats must match the following regexp:

/^\%\d+(\.\d+)?([scduxoefg]|l[duxo])$/

AUTHOR

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Colin Kuskie, ckuskie@cpan.org

KUDOS

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Many thanks to Steven McDougall for his comments about the content and style of my module and for sending me his templates for module creation. They can be found at:

http://world.std.com/~swmcd/steven/Perl/index.html

and I highly recommend them for beginning module writers.

Also thanks to Tom Christiansen for the perltoot podpage.

Convert-SciEng documentation Contained in the Convert-SciEng distribution. 
package Convert::SciEng;

use strict;
use vars qw( $VERSION ) ;
use Carp;

require 5.004_04;      ##Last standard version of Perl that I use

$VERSION = '0.91';

# Preloaded methods go here.

##Begin forming the lookup hashes using arrays
my @SP_Postfixs = qw(   P    T    g    x    k        m    u    n     p     f     a);
my @SI_Postfixs = qw(   P    T    G    M    K        m    u    n     p     f     a);
my @factors     = qw(1e15 1e12  1e9  1e6  1e3 1e0 1e-3 1e-6 1e-9 1e-12 1e-15 1e-18);
my @CS_Postfixs = qw(    P     T     G     M     K     );
my @CS_factors  =   (2**50,2**40,2**30,2**20,2**10,2**0);

##Form the regexp for extracting the suffixes
my $SP_Suffixes = join '','[',@SP_Postfixs,']';
my $SI_Suffixes = join '','[',@SI_Postfixs,']';
my $CS_Suffixes = join '','[',@CS_Postfixs,']';

##Add the null index for unity
splice (@SP_Postfixs,5,0,'');
splice (@SI_Postfixs,5,0,'');
push   (@CS_Postfixs,   ,'');

##Form the lookup hashes
my %SP_Postfixs;
@SP_Postfixs{@SP_Postfixs} = @factors;

my %SI_Postfixs;
@SI_Postfixs{@SI_Postfixs} = @factors;

my %CS_Postfixs;
@CS_Postfixs{@CS_Postfixs} = @CS_factors;

sub new {
  my $proto = shift;
  my $class = ref($proto) || $proto;
  my $self = {};
  my $mode = shift;
  $mode = lc $mode;
  if ($mode eq 'spice') {
    $self->{'_SUFFIX'} = $SP_Suffixes;
    $self->{'_FACTORS'}  = \%SP_Postfixs;
    $self->{'_POSTFIXS'}  = \@SP_Postfixs;
  }
  elsif ($mode eq 'si') {
    $self->{'_SUFFIX'} = $SI_Suffixes;
    $self->{'_FACTORS'}  = \%SI_Postfixs;
    $self->{'_POSTFIXS'}  = \@SI_Postfixs;
  }
  elsif ($mode eq 'cs') {
    $self->{'_SUFFIX'} = $CS_Suffixes;
    $self->{'_FACTORS'}  = \%CS_Postfixs;
    $self->{'_POSTFIXS'}  = \@CS_Postfixs;
  }
  else {
    croak "Unrecoginized mode: $mode\n";
  }
  $self->{FORMAT} = '%5.5g';
  bless ($self,$class);
  return $self;
}

sub format {
  my $self = shift;
  return $self->{FORMAT} unless scalar @_;
  my $format = shift;
  unless ($format =~ /^\%\d+(\.\d+)?([scduxoefg]|l[duxo])$/) {
    croak "Illegal printf format: $format";
  }
  $self->{FORMAT} = $format;
  return $self->{FORMAT};
}

# remove postfix scale factor and convert to scientific
sub unfix {
  my $self = shift;
  my $char;
  my @num = @_;
  for (@num) {
    next unless index($self->{'_SUFFIX'}, substr($_,-1,1)) != -1;
    $char = chop; ##Remove that character
    $_ *= $self->{'_FACTORS'}->{$char};
  }
  return wantarray ? @num : $num[0];
}

# add postfix scale factor and convert from scientific
sub fix {
  my $self = shift;
  my (@SciNum) = @_;
  my ($pfix,$y);
  NUMBER: for (@SciNum) {
    $y = abs($_);
    foreach $pfix (@{ $self->{'_POSTFIXS'} }) {
      if ($y >= $self->{'_FACTORS'}->{$pfix}) {
	$_ = sprintf("$self->{FORMAT}${pfix}",$_/$self->{'_FACTORS'}->{$pfix});
	next NUMBER;
      }
    }
  }
  return wantarray ? @SciNum : $SciNum[0];
}

1;

__END__


1;