Base Representation

This module is for represent Python data in the desired base system, like Base36 and Base62.

Introduce

This supports from 2 base systems to 62 base systems that can be expressed only with digits and case sensitive alphabets.

This module was developed to make it easier to use for URLs or other data fields requiring length restrictions by expressing large numbers or hash values to a shorter length.

You can also encode strings or decode encoded strings. (Strings are not guaranteed to be shortened.)

This started with inspiration from base62 idea and numpy.base_repr library and aim to be universally used in multiple systems such as Base36 in systems where Base62 cannot be applied because it is case-insensitive systems.

Installing Base Representation

Base Representation is available on PyPI:

$ python -m pip install base-repr

Base Representation is tested on Python 3.7+

How to use

Using functions

>>> import base_repr
# Number to string representation
>>> base_repr.int_to_repr(1234, base=62)
'Ju'
>>> base_repr.repr_to_int('Ju', base=62)
1234

# Bytes to string representation
# bytes([1, 2, 3, 4]) == b'\x01\x02\x03\x04'
>>> base_repr.bytes_to_repr(bytes([1, 2, 3, 4]), base=62, byteorder='little')
'4YPMP'
>>> base_repr.repr_to_bytes('4YPMP', base=62, byteorder='little')
b'\x01\x02\x03\x04'

# sha256
import hashlib
# hashlib.sha256(b'Hello World!').hexdigest() == '7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069'
>>> base_repr.bytes_to_repr(hashlib.sha256(b'Hello World!').digest(), base=62, byteorder='little')
'P20z9unz25ZdkS9kKi65j9Rb8jqP5knHG08sDpvsQDn'

# string
>>> base_repr.str_to_repr('Hello', base=62, byteorder='little', encoding='utf-8')
'8QMwioi'
>>> base_repr.repr_to_str('8QMwioi', base=62, byteorder='little', encoding='utf-8')
'Hello'

# simple wrapper to union above 3 functions for data type int, bytes and str.
>>> base_repr.to_repr('int or bytes or str', base=62)
'3xDXjUL88hX1Dq95EbXKCI7cOP'

Choose your base to represent (or from representation)

You can choose base system from 2 to 62. 2 is used by default.

>>> import base_repr
>>> base_repr.to_repr(1234)
'10011010010'
>>> base_repr.to_repr(1234, base=2)
'10011010010'
>>> base_repr.to_repr(1234, base=16)
'4D2'
>>> base_repr.to_repr(1234, base=62)
'Ju'

Choose padding to represent

You can use padding to fit the number of digits you want. The default is 0.

>>> base_repr.to_repr(10, padding=10)
'0000001010'
>>> base_repr.repr_to_int('0000001010')
10

Choose your byteorder which 'little' or 'big'

You can choose byteorder from 'little' or 'big' for bytes or str data type. System values (sys.byteorder) are used by default.

>>> import base_repr
>>> base_repr.to_repr('Hello', base=62, byteorder='little')
'8QMwioi'
>>> base_repr.repr_to_str('8QMwioi', base=62, byteorder='little')
'Hello'

>>> base_repr.to_repr('Hello', base=62, byteorder='big')
'5TP3P3v'
>>> base_repr.repr_to_str('5TP3P3v', base=62, byteorder='big')
'Hello'

Choose your encoding

You can choose encoding to represent (from representation) str data type. The default is 'utf-8'.

>>> import base_repr
>>> base_repr.to_repr('English', base=62, encoding='utf-8')
'2AeWfKYcJ3'
>>> base_repr.repr_to_str('2AeWfKYcJ3', base=62, encoding='utf-8')
'English'

>>> base_repr.to_repr('한글', base=62, encoding='utf-8')
'eBkBTHSP'
>>> base_repr.repr_to_str('eBkBTHSP', base=62, encoding='utf-8')
'한글'

>>> base_repr.to_repr('🍺', base=62, encoding='utf-16')
'17m0y4sjX'
>>> base_repr.repr_to_str('17m0y4sjX', base=62, encoding='utf-16')
'🍺'

Using class

You can use classes to reduce repetitive parameters.

>>> from base_repr import Base62
>>> base62 = Base62(byteorder='little', encoding='utf-8')
>>> base62.bytes_to_repr(bytes([1, 2, 3, 4]))
'4YPMP'
>>> base62.repr_to_bytes('4YPMP')
b'\x01\x02\x03\x04'
>>> base62.to_repr('int or bytes or str')
'3xDXjUL88hX1Dq95EbXKCI7cOP'

You can also inherit a base class to create your own desired base system simply.

>>> from base_repr import BaseRepr
>>> class Base36(BaseRepr):
... def __init__(self, padding: int = 0, byteorder: str = sys.byteorder, encoding: str = 'utf-8'):
...     super().__init__(36, padding, byteorder, encoding)

>>> base = Base36(padding=0, byteorder='big', encoding='utf-8')
>>> base.int_to_repr(1234)
'YA'
>>> base.repr_to_int('YA')
1234

Base62 and Base36 are already defined in module and ready to use.