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thomascrenshaw/notes-base36

Last active November 18, 2020 19:07
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Revisions

  1. thomascrenshaw revised this gist Oct 17, 2013. 1 changed file with 4 additions and 0 deletions.
    4 changes: 4 additions & 0 deletions notes-base36
    View file
    Original file line number Diff line number Diff line change
    @@ -34,6 +34,10 @@ print base36decode('AQF8AA0006EH')
    parseInt("kf12oi",36) // => 1234567890
    ----
    SOURCE: http://en.wikipedia.org/wiki/Base_36
    ----
    # math example
    (FACE)36 = 15*363 + 10*362 + 12*36 + 14.
    SOURCE: http://primes.utm.edu/notes/words.html

    USES IN PRACTICE:
    tinyurl -- use base 36 integers as compact alphanumeric identifiers
  2. thomascrenshaw created this gist Oct 17, 2013.
    45 changes: 45 additions & 0 deletions notes-base36
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,45 @@
    # php
    <?php print base_convert("12abcxyz",36,10); ?>
    ----
    #python
    def base36encode(number, alphabet='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'):
    """Converts an integer to a base36 string."""
    if not isinstance(number, (int, long)):
    raise TypeError('number must be an integer')

    base36 = ''
    sign = ''

    if number < 0:
    sign = '-'
    number = -number

    if 0 <= number < len(alphabet):
    return sign + alphabet[number]

    while number != 0:
    number, i = divmod(number, len(alphabet))
    base36 = alphabet[i] + base36

    return sign + base36

    def base36decode(number):
    return int(number, 36)

    print base36encode(1412823931503067241)
    print base36decode('AQF8AA0006EH')
    ----
    # javascript
    (1234567890).toString(36) // => "kf12oi"
    parseInt("kf12oi",36) // => 1234567890
    ----
    SOURCE: http://en.wikipedia.org/wiki/Base_36

    USES IN PRACTICE:
    tinyurl -- use base 36 integers as compact alphanumeric identifiers
    reddit -- uses base-36 for identifying posts and comments.

    INTERESTING
    http://primes.utm.edu/notes/words.html - prime numbers that are words in Base36
    WIKIPEDIA (Base36) == 91,730,738,691,298 (decimal)