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Any Base Converter (gallery-any-base-converter) on cdn

Last Updated: 06/21/12

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Steven Olmsted

YUI Contributor

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Created: 02/22/12
Last CDN Push: 05/2/13
Build Tag: gallery-2013.05.02-22-59
Project: YUI 3
License: YUI BSD
YUI Version: 3.5.1
Free for use.

Y.AnyBaseConverter is an object that will convert numbers to and from a positional notation with a custom alphabet and base.

Numbers are generally displayed in base ten. This means there are ten single-digit numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9) before the first two-digit number, 10. Sometimes it is useful to work with numbers in other bases. Base 2, base 8, and base 16 tend to come up frequently in programming. JavaScript provides a toString method on numbers which can convert a number to any base from base 2 to base 36 and a parseInt function for converting the strings back into numbers. For bases greater than 10, lower-case letters are used for single digits greater than 9. For example, base 16 uses these single-digit numbers: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, and f.

Y.AnyBaseConverter is very similar to number.toString and parseInt except it can convert to and from bases greater than 36 and use a custom alphabet to represent the single-digit numbers. In addition to any convenient mathematical properties, it may be helpful to convert to a higher base as a simple way to compress a large number as a string or to use a custom alphabet as a method of obfuscation.

More information about positional notation and bases:
http://en.wikipedia.org/wiki/Positional_notation
http://en.wikipedia.org/wiki/Radix

Y.AnyBaseConverter has three attributes:

alphabet: The string of characters to use as single-digit numbers. The length of this string determines the base of the result. Each character should be unique within the string or else it will be impossible to correctly convert a string back into a number.

minusSign: A single character string to prepend to negative values. This character should not be in the alphabet.

radixPoint: A single character string to insert between the integer and fractional parts of the number. This character should not be in the alphabet.

Y.AnyBaseConverter has two methods:

from(string): converts a string from a custom base and returns a number.

to(number): converts a number to a custom base and returns a string.

Y.AnyBaseConverter currently does not support non-BMP characters.

With a proper alphabet, Y.AnyBaseConverter can produce the same results as number.toString(n) and parseInt(string, n) when working with integer values. Y.AnyBaseConverter handles the fractional part of a number differently.

Code Sample

<script src="http://yui.yahooapis.com/3.5.1/build/yui/yui-min.js"></script>

YUI({
    //Last Gallery Build of this module
    gallery: 'gallery-2013.05.02-22-59'
}).use('gallery-any-base-converter', function(Y) {
    var converter;
 
    // By default, Y.AnyBaseConverter comes with a base 64 alphabet which supports
    // floating-point numbers, negative numbers, and is completely URL safe.
    // (This is not quite the same thing as base 64 encoding.)
 
    converter = new Y.AnyBaseConverter();
 
    // convert a number to a string
    converter.to(1234567);
    // returns '4iQ7'
 
    // convert a string to a number
    converter.from('4iQ7');
    // returns 1234567
 
    // Here are some other alphabets to try:
 
    //
    // Binary - Used primarily by computer hardware.
    //
 
    converter = new Y.AnyBaseConverter({
        alphabet: '01'
    });
 
    converter.to(1234567);
    // returns '100101101011010000111'
 
    //
    // Base 58 - Only uses alphanumeric digits that are easily human readable.
    //
 
    converter = new Y.AnyBaseConverter({
        alphabet: '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
    });
 
    converter.to(1234567);
    // returns '7Kze'
 
    //
    // Confusing - Same base, same characters, different order.
    //
 
    converter = new Y.AnyBaseConverter({
        alphabet: '8641359207'
    });
 
    converter.to(1234567);
    // returns '6413592'
});

YUI({
    //Last Gallery Build of this module
    gallery: 'gallery-2013.05.02-22-59'
}).use('gallery-any-base-converter', function(Y) {
    var converter;

// By default, Y.AnyBaseConverter comes with a base 64 alphabet which supports
    // floating-point numbers, negative numbers, and is completely URL safe.
    // (This is not quite the same thing as base 64 encoding.)

converter = new Y.AnyBaseConverter();

// convert a number to a string
    converter.to(1234567);
    // returns '4iQ7'

// convert a string to a number
    converter.from('4iQ7');
    // returns 1234567

// Here are some other alphabets to try:

//
    // Binary - Used primarily by computer hardware.
    //

converter = new Y.AnyBaseConverter({
        alphabet: '01'
    });

converter.to(1234567);
    // returns '100101101011010000111'

//
    // Base 58 - Only uses alphanumeric digits that are easily human readable.
    //

converter = new Y.AnyBaseConverter({
        alphabet: '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
    });

converter.to(1234567);
    // returns '7Kze'

//
    // Confusing - Same base, same characters, different order.
    //

converter = new Y.AnyBaseConverter({
        alphabet: '8641359207'
    });

converter.to(1234567);
    // returns '6413592'
});