Common utility functions for ethereum codebases.
Project description
Common utility functions for codebases which interact with ethereum.
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
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 kwei babbage femtoether mwei lovelace picoether gwei shannon nanoether nano szabo microether micro finney milliether milli ether kether grand mether gether tether |
1 1000 1000 1000 1000000 1000000 1000000 1000000000 1000000000 1000000000 1000000000 1000000000000 1000000000000 1000000000000 1000000000000000 1000000000000000 1000000000000000 1000000000000000000 1000000000000000000000 1000000000000000000000 1000000000000000000000000 1000000000000000000000000000 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
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