NAME

Math::NumSeq::DigitCount -- count of a given digit

SYNOPSIS

use Math::NumSeq::DigitCount;
my $seq = Math::NumSeq::DigitCount->new (radix => 10,
                                         digit => 9);
my ($i, $value) = $seq->next;

DESCRIPTION

The count of how many of a given digit is in $i when written out in a given radix. The default is to count how many 9s in decimal.

# starting i=0
0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, ...

For example i=19 has a single "9" so value=1.

The radix and digit options can select a different number base or different digit to count. For example to count the 0-bits in binary,

# radix=>2, digit=>0
# starting i=0
0, 0, 1, 0, 2, 1, 1, 0, 3, 2, 2, 1, 2, 1, 1, 0, 4, 3, 3, 2, ...

i=0 is treated as no digits at all, so it has value=0 for the count of 0-bits, and similarly in other bases counting 0 digits.

Option digit => -1 gives the highest digit in the radix, ie. radix-1. This is the default, so if radix is given the count is of its biggest digit.

FUNCTIONS

See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence classes.

$seq = Math::NumSeq::DigitCount->new (radix => $r, digit => $d)

Create and return a new sequence object.

digit can be -1 to mean digit radix-1, the highest digit in the radix.

Random Access

$value = $seq->ith($i)

Return how many of the given digit is in $i written in radix.

$bool = $seq->pred($value)

Return true if $value might occur as a digit count, which means simply $value>=0.

SEE ALSO

Math::NumSeq, Math::NumSeq::DigitLength, Math::NumSeq::RadixWithoutDigit

HOME PAGE

http://user42.tuxfamily.org/math-numseq/index.html

LICENSE

Copyright 2010, 2011, 2012, 2013 Kevin Ryde

Math-NumSeq is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

Math-NumSeq is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Math-NumSeq. If not, see <http://www.gnu.org/licenses/>.