Ethereum Utils

Common utility functions for codebases which interact with ethereum.

This library and repository was previously located at https://github.com/pipermerriam/ethereum-utils. It was transferred to the Ethereum foundation github in November 2017 and renamed to eth-utils. The PyPi package was also renamed from ethereum-utils to `eth-utils.

Installation

pip install eth-utils

Development

Clone the repository and then run:

pip install -e . -r requirements-dev.txt

Running the tests

You can run the tests with:

py.test tests

Or you can install tox to run the full test suite.

Releasing

Pandoc is required for transforming the markdown README to the proper format to render correctly on pypi.

For Debian-like systems:

apt install pandoc

Or on OSX:

brew install pandoc

To release a new version:

bumpversion $$VERSION_PART_TO_BUMP$$
git push && git push --tags
make release

How to bumpversion

The version format for this repo is {major}.{minor}.{patch} for stable, and {major}.{minor}.{patch}-{stage}.{devnum} for unstable (stage can be alpha or beta).

To issue the next version in line, use bumpversion and specify which part to bump, like bumpversion minor or bumpversion devnum.

If you are in a beta version, bumpversion stage will switch to a stable.

To issue an unstable version when the current version is stable, specify the new version explicitly, like bumpversion --new-version 4.0.0-alpha.1 devnum

Documentation

All functions can be imported directly from the eth_utils module

ABI Utils

event_abi_to_log_topic(event_abi) -> bytes

Returns the 32 byte log topic for the given event abi.

>>> event_abi_to_log_topic({'type': 'event', 'anonymous': False, 'name': 'MyEvent', 'inputs': []})
b'M\xbf\xb6\x8bC\xdd\xdf\xa1+Q\xeb\xe9\x9a\xb8\xfd\xedb\x0f\x9a\n\xc21B\x87\x9aO\x19*\x1byR\xd2'

event_signature_to_log_topic(event_signature) -> bytes

Returns the 32 byte log topic for the given event signature.

>>> event_signature_to_log_topic('MyEvent()')
b'M\xbf\xb6\x8bC\xdd\xdf\xa1+Q\xeb\xe9\x9a\xb8\xfd\xedb\x0f\x9a\n\xc21B\x87\x9aO\x19*\x1byR\xd2'

function_abi_to_4byte_selector(function_abi) -> bytes

Returns the 4 byte function selector for the given function abi.

>>> function_abi_to_4byte_selector({'type': 'function', 'name': 'myFunction', 'inputs': [], 'outputs': []})
b'\xc3x\n:'

function_signature_to_4byte_selector(function_signature) -> bytes

Returns the 4 byte function selector for the given function signature.

>>> function_signature_to_4byte_selector('myFunction()')
b'\xc3x\n:'

Address Utils

is_address(value) -> bool

Returns True if the value is one of the following accepted address formats.

• 20 byte hexidecimal, upper/lower/mixed case, with or without 0x prefix:
  • 'd3cda913deb6f67967b99d67acdfa1712c293601'
  • '0xd3cda913deb6f67967b99d67acdfa1712c293601'
  • '0xD3CDA913DEB6F67967B99D67ACDFA1712C293601'
  • '0xd3CdA913deB6f67967B99D67aCDFa1712C293601'
• 20 byte hexidecimal padded to 32 bytes with null bytes, upper/lower/mixed case, with or without 0x prefix:
  • '000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601'
  • '000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601'
  • '0x000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601'
  • '0x000000000000000000000000D3CDA913DEB6F67967B99D67ACDFA1712C293601'
  • '0x000000000000000000000000d3CdA913deB6f67967B99D67aCDFa1712C293601'
• 20 text or bytes string:
  • '\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01'
• 20 text or bytes string padded to 32 bytes with null bytes.
  • '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01'

This function has two special cases when it will return False:

• a 20-byte hex string that has mixed case, with an invalid checksum
• a 32-byte value that is all null bytes

>>> is_address('d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
True
>>> is_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_address('0x000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_address('0x000000000000000000000000D3CDA913DEB6F67967B99D67ACDFA1712C293601')
True
>>> is_address('0x000000000000000000000000d3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
True
>>> is_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
True
>>> is_address('0x0000000000000000000000000000000000000000000000000000000000000000')
False
>>> is_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
False

is_hex_address(value) => bool

Return True if the value is a 20 byte hexidecimal encoded string in any of upper/lower/mixed casing, with or without the 0x prefix. Otherwise return False

• 'd3cda913deb6f67967b99d67acdfa1712c293601'
• '0xd3cda913deb6f67967b99d67acdfa1712c293601'
• '0xD3CDA913DEB6F67967B99D67ACDFA1712C293601'
• '0xd3CdA913deB6f67967B99D67aCDFa1712C293601'

>>> is_hex_address('d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_hex_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_hex_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
True
>>> is_hex_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_hex_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_hex_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_hex_address('0x000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_hex_address('0x000000000000000000000000D3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_hex_address('0x000000000000000000000000d3CdA913deB6f67967B99D67aCDFa1712C293601')
False
>>> is_hex_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
False
>>> is_hex_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
False
>>> is_hex_address('0x0000000000000000000000000000000000000000000000000000000000000000')
False
>>> is_hex_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
False

is_binary_address(value) -> bool

Return True if the value is a 20 byte string.

>>> is_binary_address('d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_binary_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_binary_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_binary_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
False
>>> is_binary_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_binary_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_binary_address('0x000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_binary_address('0x000000000000000000000000D3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_binary_address('0x000000000000000000000000d3CdA913deB6f67967B99D67aCDFa1712C293601')
False
>>> is_binary_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
True
>>> is_binary_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
False
>>> is_binary_address('0x0000000000000000000000000000000000000000000000000000000000000000')
False
>>> is_binary_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
False

is_32byte_address(value) -> bool

Return True if the value is a 20 byte address that has been padded to 32 bytes. This function allows both bytes or hexidecimal encoded strings. Hexidecimal strings may optionally be 0x prefixed. The padding bytes must be zeros.

Note: this method returns false for the zero address.

>>> is_32byte_address('d3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_32byte_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_32byte_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_32byte_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
False
>>> is_32byte_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_32byte_address('000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_32byte_address('0x000000000000000000000000d3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_32byte_address('0x000000000000000000000000D3CDA913DEB6F67967B99D67ACDFA1712C293601')
True
>>> is_32byte_address('0x000000000000000000000000d3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_32byte_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
False
>>> is_32byte_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')
True
>>> is_32byte_address('0x0000000000000000000000000000000000000000000000000000000000000000')
False
>>> is_32byte_address('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
False

is_canonical_address(value) -> bool

Returns True if the value is an address in it's canonical form.

The canonical representation of an address according to eth_utils is a 20 byte long string of bytes, eg: b'\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01'

>>> is_canonical_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_canonical_address(b'\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd')
True
>>> is_canonical_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd')
False

is_checksum_address(value) -> bool

Returns True if the value is a checksummed address as specified by ERC55

>>> is_checksum_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_checksum_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_checksum_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_checksum_address('0x52908400098527886E0F7030069857D2E4169EE7')
True
>>> is_checksum_address('0xde709f2102306220921060314715629080e2fb77')
True

is_checksum_formatted_address(value) -> bool

Returns True if the value is formatted as an ERC55 checksum address.

>>> is_checksum_formatted_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_checksum_formatted_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False
>>> is_checksum_formatted_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_checksum_formatted_address('0x52908400098527886E0F7030069857D2E4169EE7')
False
>>> is_checksum_formatted_address('0xde709f2102306220921060314715629080e2fb77')
False

is_normalized_address(value) -> bool

Returns True if the value is an address in its normalized form.

The normalized representation of an address is the lowercased 20 byte hexidecimal format.

>>> is_normalized_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
False
>>> is_normalized_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
True
>>> is_normalized_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
False
>>> is_normalized_address('0x52908400098527886E0F7030069857D2E4169EE7')
False
>>> is_normalized_address('0xde709f2102306220921060314715629080e2fb77')
True

is_same_address(a, b) -> bool

Returns True if both a and b are valid addresses according to the is_address function and that they are both representations of the same address.

>>> is_same_address('0xd3cda913deb6f67967b99d67acdfa1712c293601', '0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
True
>>> is_same_address('0xd3cda913deb6f67967b99d67acdfa1712c293601', '0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> is_same_address('0xd3cda913deb6f67967b99d67acdfa1712c293601', '\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd')
True

to_canonical_address(value) -> bytes

Given any valid representation of an address return it's canonical form.

>>> to_canonical_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
b'\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd'
>>> to_canonical_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
b'\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd'
>>> to_canonical_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
b'\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd'
>>> to_canonical_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd')
b'\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd'

to_checksum_address(value) -> text

Given any valid representation of an address return the checksummed representation.

>>> to_checksum_address('0xd3cda913deb6f67967b99d67acdfa1712c293601')
'0xd3CdA913deB6f67967B99D67aCDFa1712C293601'
>>> to_checksum_address('0xD3CDA913DEB6F67967B99D67ACDFA1712C293601')
'0xd3CdA913deB6f67967B99D67aCDFa1712C293601'
>>> to_checksum_address('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
'0xd3CdA913deB6f67967B99D67aCDFa1712C293601'
>>> to_checksum_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01xd')
'0xd3CdA913deB6f67967B99D67aCDFa1712C293601'

to_normalized_address(value) -> text

Given any valid representation of an address return the normalized representation.

>>> to_normalized_address('\xd3\xcd\xa9\x13\xde\xb6\xf6yg\xb9\x9dg\xac\xdf\xa1q,)6\x01')  # raw bytes
'0xd3cda913deb6f67967b99d67acdfa1712c293601'
>>> to_normalized_address(b'0xc6d9d2cd449a754c494264e1809c50e34d64562b')  # hex encoded (as byte string)
'0xc6d9d2cd449a754c494264e1809c50e34d64562b'
>>> to_normalized_address('0xc6d9d2cd449a754c494264e1809c50e34d64562b')  # hex encoded
'0xc6d9d2cd449a754c494264e1809c50e34d64562b'
>>> to_normalized_address('0XC6D9D2CD449A754C494264E1809C50E34D64562B')  # cap-cased
'0xc6d9d2cd449a754c494264e1809c50e34d64562b'
>>> to_normalized_address('0x000000000000000000000000c305c901078781c232a2a521c2af7980f8385ee9')  # padded to 32 bytes
'0xc305c901078781c232a2a521c2af7980f8385ee9',

Crypto Utils

keccak(value) -> bytes

Given any string returns the sha3/keccak hash. If value is not a byte string it will be converted using the force_bytes function.

>>> keccak('')
b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p"

Currency Utils

denoms

Object with property access to all of the various denominations for ether. Available denominations are:

+--------------+---------------------------------+ | denomination | amount in wei | +--------------+---------------------------------+ | wei | 1 | | kwei | 1000 | | babbage | 1000 | | femtoether | 1000 | | mwei | 1000000 | | lovelace | 1000000 | | picoether | 1000000 | | gwei | 1000000000 | | shannon | 1000000000 | | nanoether | 1000000000 | | nano | 1000000000 | | szabo | 1000000000000 | | microether | 1000000000000 | | micro | 1000000000000 | | finney | 1000000000000000 | | milliether | 1000000000000000 | | milli | 1000000000000000 | | ether | 1000000000000000000 | | kether | 1000000000000000000000 | | grand | 1000000000000000000000 | | mether | 1000000000000000000000000 | | gether | 1000000000000000000000000000 | | tether | 1000000000000000000000000000000 | +--------------+---------------------------------+

>>> denoms.wei
1
>>> denoms.finney
1000000000000000
>>> denoms.ether
1000000000000000000

to_wei(value, denomination) -> integer

Converts value in the given denomination to its equivalent in the wei denomination.

>>> to_wei(1, 'ether')
1000000000000000000

from_wei(value, denomination) -> decimal.Decimal

Converts the value in the wei denomination to its equivalent in the given denomination. Return value is a decimal.Decimal with the appropriate precision to be a lossless conversion.

>>> from_wei(1000000000000000000, 'ether')
Decimal('1')
>>> from_wei(123456789, 'ether')
Decimal('1.23456789E-10')

Encoding Utils

big_endian_to_int(value) -> integer

Returns value converted to an integer (from a big endian representation).

>>> big_endian_to_int(b'\x00')
0
>>> big_endian_to_int(b'\x01')
1
>>> big_endian_to_int(b'\x01\x00')
256

int_to_big_endian(value) -> bytes

Returns value converted to the big endian representation.

>>> int_to_big_endian(0)
b'\x00'
>>> int_to_big_endian(1)
b'\x01'
>>> int_to_big_endian(256)
b'\x01\x00'

Formatting Utils

pad_left(value, to_size, pad_with) -> string

Returns value padded to the length specified by to_size with the string pad_with.

>>> pad_left('test', 6, '0')
'00test'
>>> pad_left('testing', 6, '0')
'testing'
>>> pad_left('test', 8, '123')
'12312test'

pad_right(value, to_size, pad_with) -> string

Returns value padded to the length specified by to_size with the string pad_with.

>>> pad_right('test', 6, '0')
'test00'
>>> pad_right('testing', 6, '0')
'testing'
>>> pad_right('test', 8, '123')
'test12312'

Functional Utils

compose(*callables) -> callable

DEPRECATED in 0.3.0.

Returns a single function which is the composition of the given callables.

>>> def f(v):
...     return v * 3
...
>>> def g(v):
...     return v + 2
...
>>> def h(v):
...     return v % 5
...
>>> compose(f, g, h)(1)
0
>>> h(g(f(1)))
0
>>> compose(f, g, h)(2)
3
>>> h(g(f(1)))
3
>>> compose(f, g, h)(3)
1
>>> h(g(f(1)))
1
>>> compose(f, g, h)(4)
4
>>> h(g(f(1)))
4

flatten_return(callable) -> callable() -> tuple

Decorator which performs a non-recursive flattening of the return value from the given callable.

>>> flatten_return(lambda: [[1, 2, 3], [4, 5], [6]])
(1, 2, 3, 4, 5, 6)

sort_return(callable) => callable() -> tuple

Decorator which sorts the return value from the given callable.

>>> flatten_return(lambda: [[1, 2, 3], [4, 5], [6]])
(1, 2, 3, 4, 5, 6)

reversed_return(callable) => callable() -> tuple

Decorator which reverses the return value from the given callable.

>>> reversed_return(lambda: [1, 5, 2, 4, 3])
(3, 4, 2, 5, 1)

to_dict(callable) => callable() -> dict

Decorator which casts the return value from the given callable to a dictionary.

>>> @to_dict
... def build_thing():
...     yield 'a', 1
...     yield 'b', 2
...     yield 'c', 3
...
>>> build_thing()
{'a': 1, 'b': 2, 'c': 3}

to_list(callable) => callable() -> list

Decorator which casts the return value from the given callable to a list.

>>> @to_list
... def build_thing():
...     yield 'a'
...     yield 'b'
...     yield 'c'
...
>>> build_thing()
['a', 'b', 'c']

to_ordered_dict(callable) => callable() -> collections.OrderedDict

Decorator which casts the return value from the given callable to an ordered dictionary of type collections.OrderedDict.

>>> @to_ordered_dict
... def build_thing():
...     yield 'd', 4
...     yield 'a', 1
...     yield 'b', 2
...     yield 'c', 3
...
>>> build_thing()
OrderedDict([('d', 4), ('a', 1), ('b', 2), ('c', 3)])

to_tuple(callable) => callable() -> tuple

Decorator which casts the return value from the given callable to a tuple.

>>> @to_tuple
... def build_thing():
...     yield 'a'
...     yield 'b'
...     yield 'c'
...
>>> build_thing()
('a', 'b', 'c')

to_set(callable) => callable() -> set

Decorator which casts the return value from the given callable to a set.

>>> @to_set
... def build_thing():
...     yield 'a'
...     yield 'b'
...     yield 'a'  # duplicate
...     yield 'c'
...
>>> build_thing()
{'a', 'b', 'c'}

apply_to_return_value(callable) => decorator_fn

This function takes a single callable and returns a decorator. The returned decorator, when applied to a function, will incercept the function's return value, pass it to the callable, and return the value returned by the callable.

>>> double = apply_to_return_value(lambda v: v * 2)
>>> @double
... def f(v):
...     return v
...
>>> f(2)
4
>>> f(3)
6

Hexidecimal Utils

add_0x_prefix(value) -> string

Returns value with a 0x prefix. If the value is already prefixed it is returned as-is.

>>> add_0x_prefix('12345')
'0x12345'
>>> add_0x_prefix('0x12345')
'0x12345'

decode_hex(value) -> bytes

Returns value decoded into a byte string. Accepts any string with or without the 0x prefix.

>>> decode_hex('0x123456')
b'\x124V'
>>> decode_hex('123456')
b'\x124V'

encode_hex(value) -> string

Returns value encoded into a hexidecimal representation with a 0x prefix

>>> encode_hex('\x01\x02\x03')
'0x010203'

is_0x_prefixed(value) -> bool

Returns True if value has a 0x prefix.

>>> is_0x_prefixed('12345')
False
>>> is_0x_prefixed('0x12345')
True
>>> is_0x_prefixed(b'0x12345')
True

is_hex(value) -> bool

Returns True if value is a hexidecimal encoded string.

>>> is_hex('')
False
>>> is_hex(b'')
False
>>> is_hex('0x')
True
>>> is_hex(b'0x')
True
>>> is_hex('0X')
True
>>> is_hex(b'0X')
True
>>> is_hex('1234567890abcdef')
True
>>> is_hex('0x1234567890abcdef')
True
>>> is_hex('0x1234567890ABCDEF')
True
>>> is_hex('0x1234567890AbCdEf')
True
>>> is_hex('12345')  # odd length is ok
True
>>> is_hex('0x12345')  # odd length is ok
True
>>> is_hex('123456__abcdef')  # non hex characters
False

remove_0x_prefix(value) -> string

Returns value with the 0x prefix stripped. If the value does not have a 0x prefix it is returned as-is.

>>> remove_0x_prefix('12345')
'12345'
>>> remove_0x_prefix('0x12345')
'12345'
>>> remove_0x_prefix(b'0x12345')
b'12345'

String Utils

coerce_args_to_bytes(callable) -> callable

Decorator which will convert any string arguments both positional or keyword into byte strings using the force_bytes function. This is a recursive operation which will reach down into mappings and list-like objects as well.

>>> @coerce_args_to_bytes
... def do_thing(*args):
...     return args
...
>>> do_thing('a', 1, b'a-byte-string', ['a', b'b', 1], {'a': 'a', 'b': ['x', b'y']})
(b'a', 1, b'a-byte-string', [b'a', b'b', 1], {'a': b'a', 'b': [b'x', b'y']})

coerce_args_to_text(callable) -> callable

Decorator which will convert any string arguments both positional or keyword into text strings using the force_text function. This is a recursive operation which will reach down into mappings and list-like objects as well.

>>> @coerce_args_to_text
... def do_thing(*args):
...     return args
...
>>> do_thing('a', 1, b'a-byte-string', ['a', b'b', 1], {'a': 'a', 'b': ['x', b'y']})
('a', 1, 'a-byte-string', ['a', 'b', 1], {'a': 'a', 'b': ['x', 'y']})

coerce_return_to_bytes(callable) -> callable

Decorator which will convert any string return values into byte strings using the force_text function. This is a recursive operation which will reach down into mappings and list-like objects as well.

>>> @coerce_return_to_bytes
... def do_thing(*args):
...     return args
...
>>> do_thing('a', 1, b'a-byte-string', ['a', b'b', 1], {'a': 'a', 'b': ['x', b'y']})
(b'a', 1, b'a-byte-string', [b'a', b'b', 1], {'a': b'a', 'b': [b'x', b'y']})

coerce_return_to_text(callable) -> callable

Decorator which will convert any string return values into text strings using the force_text function. This is a recursive operation which will reach down into mappings and list-like objects as well.

>>> @coerce_return_to_bytes
... def do_thing(*args):
...     return args
...
>>> do_thing('a', 1, b'a-byte-string', ['a', b'b', 1], {'a': 'a', 'b': ['x', b'y']})
('a', 1, 'a-byte-string', ['a', 'b', 1], {'a': 'a', 'b': ['x', 'y']})

force_bytes(value, encoding='iso-8859-1') -> text

Returns value encoded into a byte string using the provided encoding. By default this uses iso-8859-1 as it can handle all byte values between 0-255 (unlike utf8)

>>> force_bytes('abcd')
b'abcd'
>>> force_bytes(b'abcd')
b'abcd'

force_obj_to_bytes(value) -> value

Returns value with all string elements converted to byte strings by recursivly traversing mappings and list-like elements.

>>> force_obj_to_bytes(('a', 1, b'a-byte-string', ['a', b'b', 1], {'a': 'a', 'b': ['x', b'y']}))
(b'a', 1, b'a-byte-string', [b'a', b'b', 1], {'a': b'a', 'b': [b'x', b'y']})

force_obj_to_text(value) -> value

Returns value with all string elements converted to text strings by recursivly traversing mappings and list-like elements.

>>> force_obj_to_text(('a', 1, b'a-byte-string', ['a', b'b', 1], {'a': 'a', 'b': ['x', b'y']}))
('a', 1, 'a-byte-string', ['a', 'b', 1], {'a': 'a', 'b': ['x', 'y']})

force_text(value, encoding='iso-8859-1') -> text

Returns value decoded into a text string using the provided encoding. By default this uses iso-8859-1 as it can handle all byte values between 0-255 (unlike utf8)

>>> force_text(b'abcd')
'abcd'
>>> force_text('abcd')
'abcd'

Type Utils

is_boolean(value) -> bool

Returns True if value is of type bool

>>> is_boolean(True)
True
>>> is_boolean(False)
False
>>> is_boolean(1)
False

is_bytes(value) -> bool

Returns True if value is a byte string or a byte array.

>>> is_bytes('abcd')
False
>>> is_bytes(b'abcd')
True
>>> is_bytes(bytearray((1, 2, 3)))
True

is_dict(value) -> bool

Returns True if value is a mapping type.

>>> is_dict({'a': 1})
True
>>> is_dict([1, 2, 3])
False

is_integer(value) -> bool

Returns True if value is an integer

>>> is_integer(0)
True
>>> is_integer(1)
True
>>> is_integer('1')
False
>>> is_integer(1.1)
False

is_list_like(value) -> bool

Returns True if value is a non-string sequence such as a sequence (such as a list or tuple).

>>> is_list_like('abcd')
False
>>> is_list_like([])
True
>>> is_list_like(tuple())
True

is_list(value) -> bool

Returns True if value is a non-string sequence such as a list.

>>> is_list('abcd')
False
>>> is_list([])
True
>>> is_list(tuple())
False

is_tuple(value) -> bool

Returns True if value is a non-string sequence such as a tuple.

>>> is_tuple('abcd')
False
>>> is_tuple([])
False
>>> is_tuple(tuple())
True

is_null(value) -> bool

Returns True if value is None

>>> is_null(None)
True
>>> is_null(False)
False

is_number(value) -> bool

Returns True if value is numeric

>>> is_number(1)
True
>>> is_number(1.1)
True
>>> is_number('1')
False
>>> is_number(decimal.Decimal('1'))
True

is_string(value) -> bool

Returns True if value is of any string type.

>>> is_string('abcd')
True
>>> is_string(b'abcd')
True
>>> is_string(bytearray((1, 2, 3)))
True

is_text(value) -> bool

Returns True if value is a text string.

>>> is_text(u'abcd')
True
>>> is_text(b'abcd')
False
>>> is_text(bytearray((1, 2, 3)))
False

How to bumpversion

The version format for this repo is {major}.{minor}.{patch} for stable, and {major}.{minor}.{patch}-{stage}.{devnum} for unstable (stage can be alpha or beta).

To issue the next version in line, use bumpversion and specify which part to bump, like bumpversion minor or bumpversion devnum.

If you are in a beta version, bumpversion stage will switch to a stable.

To issue an unstable version when the current version is stable, specify the new version explicitly, like bumpversion --new-version 4.0.0-alpha.1 devnum