mirror of https://gitee.com/bigwinds/arangodb
106 lines
1.8 KiB
Markdown
106 lines
1.8 KiB
Markdown
Decimal
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======
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Simple decimal arithmetic for the browser *and* node.js!
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Why?
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=======
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Why don’t my numbers, like 0.1 + 0.2 add up to a nice round 0.3,
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and instead I get a weird result like 0.30000000000000004?
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Because internally, computers use a format (binary floating-point)
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that cannot accurately represent a number like 0.1, 0.2 or 0.3 at all.
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Source : http://floating-point-gui.de/
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I wrote this because I needed to do simple computation in the browser
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and I couldn't find a lightweight library to do it.
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How to use?
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===========
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In the browser
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--------------
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<script src="lib/decimal.js"></script>
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In node
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-------
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npm install decimal
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then in your program
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var Decimal = require('decimal');
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Examples
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=======
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>>> 1.1 + 2.2
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3.3000000000000003
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>>> Decimal('1.1').add('2.2').toNumber()
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3.3
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>>> 4.01 * 2.01
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8.060099999999998
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>>> Decimal('4.01').mul('2.01').toNumber()
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8.0601
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>>> Decimal.mul('4.01', '2.01').toNumber()
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8.0601
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Can I help?
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===========
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Of course you can, I suck at math, and this implementation is very naive.
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If you are a math Guru and you see something wrong or a
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way to simplify things you can send in a pull request.
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Methods
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=======
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Decimal(n)
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------------------
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Create a new `Decimal` from `n`. `n` can be a string, integer, or
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another `Decimal`.
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.toString()
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------------------
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Returns the `Decimal` instance as a string.
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.toNumber()
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-----------
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Turn a `Decimal` into a `Number`.
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.add(n)
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-------
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Return a new `Decimal` containing the instance value plus `n`.
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.sub(n)
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-------
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Return a new `Decimal` containing the instance value minus `n`.
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.mul(n)
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-------
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Return a new `Decimal` containing the instance value multiplied by `n`.
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.div(n)
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-------
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Return a new `Decimal` containing the instance value integrally divided by `n`.
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