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Programming Ruby The Pragmatic Programmer's Guide |
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class Bignum
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Parent:
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Integer
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Version:
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1.6
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Index:
Arithmetic operations
Bit operations
<=>
[ ]
size
to_f
to_i
to_s
Bignum objects hold integers outside the range of Fixnum. Bignum objects are created automatically when
integer calculations would otherwise overflow a Fixnum. When a
calculation involving Bignum objects returns a result that will
fit in a Fixnum, the result is automatically converted.
For the purposes of the bitwise operations and [], a Bignum is treated as if it were an infinite-length bitstring
with 2's complement representation.
While Fixnum values are immediate, Bignum objects are
not---assignment and parameter passing work with references to
objects, not the objects themselves.
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instance methods
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Arithmetic operations
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Performs various arithmetic operations on big.
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big
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+ |
aNumeric
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Addition |
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big
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-- |
aNumeric
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Subtraction |
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big
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* |
aNumeric
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Multiplication |
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big
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/ |
aNumeric
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Division |
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big
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% |
aNumeric
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Modulo |
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big
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** |
aNumeric
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Exponentiation |
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Bit operations
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Performs various operations on the binary
representations of the Bignum.
| ~ big
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Invert bits |
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big
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aNumeric
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Bitwise OR
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big
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& |
aNumeric
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Bitwise AND
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big
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^ |
aNumeric
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Bitwise EXCLUSIVE OR
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big
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<< |
aNumeric
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Left-shift aNumeric bits |
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big
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>> |
aNumeric
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Right-shift aNumeric bits
(with sign extension) |
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<=>
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big <=> aNumeric -> -1, 0, +1
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Comparison---Returns -1, 0, or +1 depending on
whether big is less
than, equal to, or greater than aNumeric. This is the
basis for the tests in Comparable.
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[ ]
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big[ n ] -> 0, 1
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Bit Reference---Returns the nth bit in
the (assumed) binary representation of big,
where big[0] is the least significant bit.
a = 9**15
50.downto(0) do |n|
print a[n]
end
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produces:
000101110110100000111000011110010100111100010111001
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size
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big.size -> anInteger
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Returns the number of bytes in the machine representation
of big.
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(256**10 - 1).size
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12
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(256**20 - 1).size
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20
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(256**40 - 1).size
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40
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to_f
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big.to_f -> aFloat
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Converts big to a Float. If big doesn't fit in a Float, the result is infinity.
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to_i
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big.to_i -> big
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Returns big.
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to_s
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big.to_s -> aString
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Returns a string containing the decimal representation of big.
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Extracted from the book "Programming Ruby -
The Pragmatic Programmer's Guide"
Copyright
©
2001 by Addison Wesley Longman, Inc. This material may
be distributed only subject to the terms and conditions set forth in
the Open Publication License, v1.0 or later (the latest version is
presently available at http://www.opencontent.org/openpub/)).
Distribution of substantively modified versions of this document is
prohibited without the explicit permission of the copyright holder.
Distribution of the work or derivative of the work in any standard
(paper) book form is prohibited unless prior permission is obtained
from the copyright holder.
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