Re: Print Number With Implied Decimal Point


There's more than one way to do things
	PerlMonks

Re: Print Number With Implied Decimal Point

by tobyink (Canon)

on Apr 18, 2012 at 14:17 UTC ( [id://965720]=note: print w/replies, xml )

Need Help??

in reply to Print Number With Implied Decimal Point

Regular expressions should work.

Alternatively, try Math::BigFloat.

use 5.010;
use Math::BigFloat;

my $number         = "999999999999999999999900";
my $decimal_places = 2;

Math::BigFloat->precision(-$decimal_places);
say Math::BigFloat->new($number)/(10**$decimal_places);
__END__
9999999999999999999999.00
[download]

substr will be faster though.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

Comment on Re: Print Number With Implied Decimal Point Select or Download Code

Replies are listed 'Best First'.

Re^2: Print Number With Implied Decimal Point
by Eliya (Vicar) on Apr 18, 2012 at 14:51 UTC

substr will be faster though.

Yes, by several orders of magnitude...

use Benchmark qw(cmpthese);
use Math::BigFloat;

Math::BigFloat->precision(-2);

my $number = "999999999999999999999900";

cmpthese -1, {
    substr   => sub { my $num=$number; substr($num,-2,0) = '.'; }, 
    BigFloat => sub { my $num=$number; Math::BigFloat->new($num)/100; 
+}, 
};

__END__
              Rate BigFloat   substr
BigFloat    3794/s       --    -100%
substr   1668189/s   43874%       --
[download]

And that doesn't even involve accessing or printing out the constructed BigFloat again.

[reply]
[d/l]

In Section Seekers of Perl Wisdom