Pure python range implementationPython implementation of SHA1ECDH implementation in pythonLSB steganography...
Why is belonging not transitive?
Delete empty subfolders, keep parent folder
Floating Point XOR
Transit visa to Hong Kong
Latex matrix formatting
Is there a generally agreed upon solution to Bradley's Infinite Regress without appeal to Paraconsistent Logic?
Why is the return value of the fun function 8 instead of 7?
Which version of the Pigeonhole principle is correct? One is far stronger than the other
How to ensure that neurotic or annoying characters don't get tiring on the long run
Statistical tests for benchmark comparison
Is my sink P-trap too low?
What's the benefit of prohibiting the use of techniques/language constructs that have not been taught?
Why are two-stroke engines nearly unheard of in aviation?
Is there a theorem in Real analysis similar to Cauchy's theorem in Complex analysis?
Travel distance across water in early prehistory
Neta Revai is achzareyos?
Is it possible that the shadow of the moon is a single dot during solar eclipse?
What does the Free Recovery sign (UK) actually mean?
Should I inform my future product owner that there are big chances that a team member will leave the company soon?
Random restarts for unsatisfiable problems
Test to know when to use GLM over Linear Regression?
Is it acceptable to use decoupling capacitor ground pad as ground for oscilloscope probe?
how to know this integral finite or infinite
What are the typical trumpet parts in classical music?
Pure python range implementation
Python implementation of SHA1ECDH implementation in pythonLSB steganography with pure PythonPython implementation for contains pattern in textPython implementation for Setiterative binary_search Python implementationis_subset Python implementationPython Float point range() operator implementationContinuous Range classPython implementation of atoi
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ margin-bottom:0;
}
7
$begingroup$
I implemented class Range as an equivalent to Python built-in range for practicing purposes. No features were added. Hope it mimics all aspects of range behavior, but maybe you can point out something I forgot. Also I tried to make the code efficient, that's why Range doesn't inherit from collections.abc.Sequence and doesn't use any of it's not abstract methods. All feedback on how to improve the code is welcome!
pyrange.py
"""
Pure Python implementation of built-in range
"""
import math
import collections.abc
import numbers
def interpret_as_integer(obj):
if hasattr(obj, '__index__'):
return obj.__index__()
raise TypeError(
''{}' object cannot be interpreted as an integer'.format(
type(obj).__name__
)
)
def adjust_indices(length, start, stop, step):
if step is None:
step = 1
else:
step = interpret_as_integer(step)
if start is None:
start = length - 1 if step < 0 else 0
else:
start = interpret_as_integer(start)
if start < 0:
start += length
if start < 0:
start = -1 if step < 0 else 0
elif start >= length:
start = length - 1 if step < 0 else length
if stop is None:
stop = -1 if step < 0 else length
else:
stop = interpret_as_integer(stop)
if stop < 0:
stop += length
if stop < 0:
stop = -1 if step < 0 else 0
elif stop >= length:
stop = length - 1 if step < 0 else length
return start, stop, step
class Range:
"""
Range(stop) -> Range object
Range(start, stop[, step]) -> Range object
Return an object that produces a sequence of integers from start (inclusive)
to stop (exclusive) by step. Range(i, j) produces i, i+1, i+2, ..., j-1.
start defaults to 0, and stop is omitted! Range(4) produces 0, 1, 2, 3.
These are exactly the valid indices for a list of 4 elements.
When step is given, it specifies the increment (or decrement).
"""
__slots__ = ('start', 'stop', 'step', '_len')
def __init__(self, start, stop=None, step=1):
if stop is None:
start, stop = 0, start
self.start, self.stop, self.step = (
interpret_as_integer(obj) for obj in (start, stop, step)
)
if step == 0:
raise ValueError('Range() arg 3 must not be zero')
step_sign = int(math.copysign(1, self.step))
self._len = max(
1 + (self.stop - self.start - step_sign) // self.step, 0
)
def __contains__(self, value):
if isinstance(value, numbers.Integral):
return self._index(value) != -1
return any(n == value for n in self)
def __eq__(self, other):
if not isinstance(other, Range):
return False
if self._len != len(other):
return False
if self._len == 0:
return True
if self.start != other.start:
return False
if self[-1] == other[-1]:
return True
return False
def __getitem__(self, index):
if isinstance(index, slice):
start, stop, step = adjust_indices(
self._len, index.start, index.stop, index.step
)
return Range(
self.start + self.step * start,
self.start + self.step * stop,
self.step * step
)
index = interpret_as_integer(index)
if index < 0:
index += self._len
if not 0 <= index < self._len:
raise IndexError('Range object index out of Range')
return self.start + self.step * index
def __hash__(self):
if self._len == 0:
return id(Range)
return hash((self._len, self.start, self[-1]))
def __iter__(self):
value = self.start
if self.step > 0:
while value < self.stop:
yield value
value += self.step
else:
while value > self.stop:
yield value
value += self.step
def __len__(self):
return self._len
def __repr__(self):
if self.step == 1:
return 'Range({}, {})'.format(self.start, self.stop)
return 'Range({}, {}, {})'.format(self.start, self.stop, self.step)
def __reversed__(self):
return iter(self[::-1])
def _index(self, value):
index_mul_step = value - self.start
if index_mul_step % self.step:
return -1
index = index_mul_step // self.step
if 0 <= index < self._len:
return index
return -1
def count(self, value):
"""
Rangeobject.count(value) -> integer
Return number of occurrences of value.
"""
return sum(1 for n in self if n == value)
def index(self, value, start=0, stop=None):
"""
Rangeobject.index(value, [start, [stop]]) -> integer
Return index of value.
Raise ValueError if the value is not present.
"""
if start < 0:
start = max(self._len + start, 0)
if stop is None:
stop = self._len
if stop < 0:
stop += self._len
if isinstance(value, numbers.Integral):
index = self._index(value)
if start <= index < stop:
return index
raise ValueError('{} is not in Range'.format(value))
i = start
n = self.start + self.step * i
while i < stop:
if n == value:
return i
i += 1
n += self.step
raise ValueError('{} is not in Range'.format(value))
collections.abc.Sequence.register(Range)
test_pyrange.py
# pylint: disable = too-few-public-methods
import itertools
from pyrange import Range
class Equal:
def __eq__(self, other):
return True
class Indexable:
def __init__(self, n):
self.n = n
def __index__(self):
return self.n
def test_basic():
small_builtin_range = range(10)
small_my_range = Range(10)
equal = Equal()
assert small_builtin_range.count(equal) == small_my_range.count(equal) == 10
assert small_my_range.index(equal) == small_my_range.index(equal) == 0
big_my_range = Range(0, 10 ** 20, 10 ** 5)
assert 10 ** 15 in big_my_range
assert big_my_range[Indexable(10 ** 3)] == 10 ** 8
assert big_my_range[
Indexable(10 ** 3):Indexable(10 ** 6):Indexable(10 ** 2)
] == Range(10 ** 8, 10 ** 11, 10 ** 7)
def test_slicing():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for slice_start, slice_stop, slice_step in itertools.product(
list(range(-3, 3)) + [None], repeat=3
):
if slice_step == 0:
continue
slc = slice(slice_start, slice_stop, slice_step)
builtin_range_slice = builtin_range[slc]
my_range_slice = my_range[slc]
for name in ('start', 'stop', 'step'):
assert (
getattr(builtin_range_slice, name) ==
getattr(my_range_slice, name)
), (start, stop, step, slice_start, slice_stop, slice_step)
def test_eq_and_hash():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for start_2, stop_2, step_2 in itertools.product(
range(-3, 3), repeat=3
):
if step_2 == 0:
continue
builtin_range_2 = range(start_2, stop_2, step_2)
my_range_2 = Range(start_2, stop_2, step_2)
if builtin_range == builtin_range_2:
assert my_range == my_range_2, (
start, stop, step, start_2, stop_2, step_2
)
assert hash(my_range) == hash(my_range_2), (
start, stop, step, start_2, stop_2, step_2
)
python reinventing-the-wheel interval
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment
|
7
$begingroup$
I implemented class Range as an equivalent to Python built-in range for practicing purposes. No features were added. Hope it mimics all aspects of range behavior, but maybe you can point out something I forgot. Also I tried to make the code efficient, that's why Range doesn't inherit from collections.abc.Sequence and doesn't use any of it's not abstract methods. All feedback on how to improve the code is welcome!
pyrange.py
"""
Pure Python implementation of built-in range
"""
import math
import collections.abc
import numbers
def interpret_as_integer(obj):
if hasattr(obj, '__index__'):
return obj.__index__()
raise TypeError(
''{}' object cannot be interpreted as an integer'.format(
type(obj).__name__
)
)
def adjust_indices(length, start, stop, step):
if step is None:
step = 1
else:
step = interpret_as_integer(step)
if start is None:
start = length - 1 if step < 0 else 0
else:
start = interpret_as_integer(start)
if start < 0:
start += length
if start < 0:
start = -1 if step < 0 else 0
elif start >= length:
start = length - 1 if step < 0 else length
if stop is None:
stop = -1 if step < 0 else length
else:
stop = interpret_as_integer(stop)
if stop < 0:
stop += length
if stop < 0:
stop = -1 if step < 0 else 0
elif stop >= length:
stop = length - 1 if step < 0 else length
return start, stop, step
class Range:
"""
Range(stop) -> Range object
Range(start, stop[, step]) -> Range object
Return an object that produces a sequence of integers from start (inclusive)
to stop (exclusive) by step. Range(i, j) produces i, i+1, i+2, ..., j-1.
start defaults to 0, and stop is omitted! Range(4) produces 0, 1, 2, 3.
These are exactly the valid indices for a list of 4 elements.
When step is given, it specifies the increment (or decrement).
"""
__slots__ = ('start', 'stop', 'step', '_len')
def __init__(self, start, stop=None, step=1):
if stop is None:
start, stop = 0, start
self.start, self.stop, self.step = (
interpret_as_integer(obj) for obj in (start, stop, step)
)
if step == 0:
raise ValueError('Range() arg 3 must not be zero')
step_sign = int(math.copysign(1, self.step))
self._len = max(
1 + (self.stop - self.start - step_sign) // self.step, 0
)
def __contains__(self, value):
if isinstance(value, numbers.Integral):
return self._index(value) != -1
return any(n == value for n in self)
def __eq__(self, other):
if not isinstance(other, Range):
return False
if self._len != len(other):
return False
if self._len == 0:
return True
if self.start != other.start:
return False
if self[-1] == other[-1]:
return True
return False
def __getitem__(self, index):
if isinstance(index, slice):
start, stop, step = adjust_indices(
self._len, index.start, index.stop, index.step
)
return Range(
self.start + self.step * start,
self.start + self.step * stop,
self.step * step
)
index = interpret_as_integer(index)
if index < 0:
index += self._len
if not 0 <= index < self._len:
raise IndexError('Range object index out of Range')
return self.start + self.step * index
def __hash__(self):
if self._len == 0:
return id(Range)
return hash((self._len, self.start, self[-1]))
def __iter__(self):
value = self.start
if self.step > 0:
while value < self.stop:
yield value
value += self.step
else:
while value > self.stop:
yield value
value += self.step
def __len__(self):
return self._len
def __repr__(self):
if self.step == 1:
return 'Range({}, {})'.format(self.start, self.stop)
return 'Range({}, {}, {})'.format(self.start, self.stop, self.step)
def __reversed__(self):
return iter(self[::-1])
def _index(self, value):
index_mul_step = value - self.start
if index_mul_step % self.step:
return -1
index = index_mul_step // self.step
if 0 <= index < self._len:
return index
return -1
def count(self, value):
"""
Rangeobject.count(value) -> integer
Return number of occurrences of value.
"""
return sum(1 for n in self if n == value)
def index(self, value, start=0, stop=None):
"""
Rangeobject.index(value, [start, [stop]]) -> integer
Return index of value.
Raise ValueError if the value is not present.
"""
if start < 0:
start = max(self._len + start, 0)
if stop is None:
stop = self._len
if stop < 0:
stop += self._len
if isinstance(value, numbers.Integral):
index = self._index(value)
if start <= index < stop:
return index
raise ValueError('{} is not in Range'.format(value))
i = start
n = self.start + self.step * i
while i < stop:
if n == value:
return i
i += 1
n += self.step
raise ValueError('{} is not in Range'.format(value))
collections.abc.Sequence.register(Range)
test_pyrange.py
# pylint: disable = too-few-public-methods
import itertools
from pyrange import Range
class Equal:
def __eq__(self, other):
return True
class Indexable:
def __init__(self, n):
self.n = n
def __index__(self):
return self.n
def test_basic():
small_builtin_range = range(10)
small_my_range = Range(10)
equal = Equal()
assert small_builtin_range.count(equal) == small_my_range.count(equal) == 10
assert small_my_range.index(equal) == small_my_range.index(equal) == 0
big_my_range = Range(0, 10 ** 20, 10 ** 5)
assert 10 ** 15 in big_my_range
assert big_my_range[Indexable(10 ** 3)] == 10 ** 8
assert big_my_range[
Indexable(10 ** 3):Indexable(10 ** 6):Indexable(10 ** 2)
] == Range(10 ** 8, 10 ** 11, 10 ** 7)
def test_slicing():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for slice_start, slice_stop, slice_step in itertools.product(
list(range(-3, 3)) + [None], repeat=3
):
if slice_step == 0:
continue
slc = slice(slice_start, slice_stop, slice_step)
builtin_range_slice = builtin_range[slc]
my_range_slice = my_range[slc]
for name in ('start', 'stop', 'step'):
assert (
getattr(builtin_range_slice, name) ==
getattr(my_range_slice, name)
), (start, stop, step, slice_start, slice_stop, slice_step)
def test_eq_and_hash():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for start_2, stop_2, step_2 in itertools.product(
range(-3, 3), repeat=3
):
if step_2 == 0:
continue
builtin_range_2 = range(start_2, stop_2, step_2)
my_range_2 = Range(start_2, stop_2, step_2)
if builtin_range == builtin_range_2:
assert my_range == my_range_2, (
start, stop, step, start_2, stop_2, step_2
)
assert hash(my_range) == hash(my_range_2), (
start, stop, step, start_2, stop_2, step_2
)
python reinventing-the-wheel interval
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
Your constructor is__init__(start, stop=None, step=1). Shouldn'tstartbe optional andstoppositional?range(3)means[0, 1, 2], not[3, 4, 5, ...].
$endgroup$
– Jack M
7 hours ago
$begingroup$
@JackM in case ofRange(3)there are linesif stop is None: start, stop = 0, start.
$endgroup$
– sanyash
7 hours ago
add a comment
|
7
7
7
$begingroup$
I implemented class Range as an equivalent to Python built-in range for practicing purposes. No features were added. Hope it mimics all aspects of range behavior, but maybe you can point out something I forgot. Also I tried to make the code efficient, that's why Range doesn't inherit from collections.abc.Sequence and doesn't use any of it's not abstract methods. All feedback on how to improve the code is welcome!
pyrange.py
"""
Pure Python implementation of built-in range
"""
import math
import collections.abc
import numbers
def interpret_as_integer(obj):
if hasattr(obj, '__index__'):
return obj.__index__()
raise TypeError(
''{}' object cannot be interpreted as an integer'.format(
type(obj).__name__
)
)
def adjust_indices(length, start, stop, step):
if step is None:
step = 1
else:
step = interpret_as_integer(step)
if start is None:
start = length - 1 if step < 0 else 0
else:
start = interpret_as_integer(start)
if start < 0:
start += length
if start < 0:
start = -1 if step < 0 else 0
elif start >= length:
start = length - 1 if step < 0 else length
if stop is None:
stop = -1 if step < 0 else length
else:
stop = interpret_as_integer(stop)
if stop < 0:
stop += length
if stop < 0:
stop = -1 if step < 0 else 0
elif stop >= length:
stop = length - 1 if step < 0 else length
return start, stop, step
class Range:
"""
Range(stop) -> Range object
Range(start, stop[, step]) -> Range object
Return an object that produces a sequence of integers from start (inclusive)
to stop (exclusive) by step. Range(i, j) produces i, i+1, i+2, ..., j-1.
start defaults to 0, and stop is omitted! Range(4) produces 0, 1, 2, 3.
These are exactly the valid indices for a list of 4 elements.
When step is given, it specifies the increment (or decrement).
"""
__slots__ = ('start', 'stop', 'step', '_len')
def __init__(self, start, stop=None, step=1):
if stop is None:
start, stop = 0, start
self.start, self.stop, self.step = (
interpret_as_integer(obj) for obj in (start, stop, step)
)
if step == 0:
raise ValueError('Range() arg 3 must not be zero')
step_sign = int(math.copysign(1, self.step))
self._len = max(
1 + (self.stop - self.start - step_sign) // self.step, 0
)
def __contains__(self, value):
if isinstance(value, numbers.Integral):
return self._index(value) != -1
return any(n == value for n in self)
def __eq__(self, other):
if not isinstance(other, Range):
return False
if self._len != len(other):
return False
if self._len == 0:
return True
if self.start != other.start:
return False
if self[-1] == other[-1]:
return True
return False
def __getitem__(self, index):
if isinstance(index, slice):
start, stop, step = adjust_indices(
self._len, index.start, index.stop, index.step
)
return Range(
self.start + self.step * start,
self.start + self.step * stop,
self.step * step
)
index = interpret_as_integer(index)
if index < 0:
index += self._len
if not 0 <= index < self._len:
raise IndexError('Range object index out of Range')
return self.start + self.step * index
def __hash__(self):
if self._len == 0:
return id(Range)
return hash((self._len, self.start, self[-1]))
def __iter__(self):
value = self.start
if self.step > 0:
while value < self.stop:
yield value
value += self.step
else:
while value > self.stop:
yield value
value += self.step
def __len__(self):
return self._len
def __repr__(self):
if self.step == 1:
return 'Range({}, {})'.format(self.start, self.stop)
return 'Range({}, {}, {})'.format(self.start, self.stop, self.step)
def __reversed__(self):
return iter(self[::-1])
def _index(self, value):
index_mul_step = value - self.start
if index_mul_step % self.step:
return -1
index = index_mul_step // self.step
if 0 <= index < self._len:
return index
return -1
def count(self, value):
"""
Rangeobject.count(value) -> integer
Return number of occurrences of value.
"""
return sum(1 for n in self if n == value)
def index(self, value, start=0, stop=None):
"""
Rangeobject.index(value, [start, [stop]]) -> integer
Return index of value.
Raise ValueError if the value is not present.
"""
if start < 0:
start = max(self._len + start, 0)
if stop is None:
stop = self._len
if stop < 0:
stop += self._len
if isinstance(value, numbers.Integral):
index = self._index(value)
if start <= index < stop:
return index
raise ValueError('{} is not in Range'.format(value))
i = start
n = self.start + self.step * i
while i < stop:
if n == value:
return i
i += 1
n += self.step
raise ValueError('{} is not in Range'.format(value))
collections.abc.Sequence.register(Range)
test_pyrange.py
# pylint: disable = too-few-public-methods
import itertools
from pyrange import Range
class Equal:
def __eq__(self, other):
return True
class Indexable:
def __init__(self, n):
self.n = n
def __index__(self):
return self.n
def test_basic():
small_builtin_range = range(10)
small_my_range = Range(10)
equal = Equal()
assert small_builtin_range.count(equal) == small_my_range.count(equal) == 10
assert small_my_range.index(equal) == small_my_range.index(equal) == 0
big_my_range = Range(0, 10 ** 20, 10 ** 5)
assert 10 ** 15 in big_my_range
assert big_my_range[Indexable(10 ** 3)] == 10 ** 8
assert big_my_range[
Indexable(10 ** 3):Indexable(10 ** 6):Indexable(10 ** 2)
] == Range(10 ** 8, 10 ** 11, 10 ** 7)
def test_slicing():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for slice_start, slice_stop, slice_step in itertools.product(
list(range(-3, 3)) + [None], repeat=3
):
if slice_step == 0:
continue
slc = slice(slice_start, slice_stop, slice_step)
builtin_range_slice = builtin_range[slc]
my_range_slice = my_range[slc]
for name in ('start', 'stop', 'step'):
assert (
getattr(builtin_range_slice, name) ==
getattr(my_range_slice, name)
), (start, stop, step, slice_start, slice_stop, slice_step)
def test_eq_and_hash():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for start_2, stop_2, step_2 in itertools.product(
range(-3, 3), repeat=3
):
if step_2 == 0:
continue
builtin_range_2 = range(start_2, stop_2, step_2)
my_range_2 = Range(start_2, stop_2, step_2)
if builtin_range == builtin_range_2:
assert my_range == my_range_2, (
start, stop, step, start_2, stop_2, step_2
)
assert hash(my_range) == hash(my_range_2), (
start, stop, step, start_2, stop_2, step_2
)
python reinventing-the-wheel interval
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I implemented class Range as an equivalent to Python built-in range for practicing purposes. No features were added. Hope it mimics all aspects of range behavior, but maybe you can point out something I forgot. Also I tried to make the code efficient, that's why Range doesn't inherit from collections.abc.Sequence and doesn't use any of it's not abstract methods. All feedback on how to improve the code is welcome!
pyrange.py
"""
Pure Python implementation of built-in range
"""
import math
import collections.abc
import numbers
def interpret_as_integer(obj):
if hasattr(obj, '__index__'):
return obj.__index__()
raise TypeError(
''{}' object cannot be interpreted as an integer'.format(
type(obj).__name__
)
)
def adjust_indices(length, start, stop, step):
if step is None:
step = 1
else:
step = interpret_as_integer(step)
if start is None:
start = length - 1 if step < 0 else 0
else:
start = interpret_as_integer(start)
if start < 0:
start += length
if start < 0:
start = -1 if step < 0 else 0
elif start >= length:
start = length - 1 if step < 0 else length
if stop is None:
stop = -1 if step < 0 else length
else:
stop = interpret_as_integer(stop)
if stop < 0:
stop += length
if stop < 0:
stop = -1 if step < 0 else 0
elif stop >= length:
stop = length - 1 if step < 0 else length
return start, stop, step
class Range:
"""
Range(stop) -> Range object
Range(start, stop[, step]) -> Range object
Return an object that produces a sequence of integers from start (inclusive)
to stop (exclusive) by step. Range(i, j) produces i, i+1, i+2, ..., j-1.
start defaults to 0, and stop is omitted! Range(4) produces 0, 1, 2, 3.
These are exactly the valid indices for a list of 4 elements.
When step is given, it specifies the increment (or decrement).
"""
__slots__ = ('start', 'stop', 'step', '_len')
def __init__(self, start, stop=None, step=1):
if stop is None:
start, stop = 0, start
self.start, self.stop, self.step = (
interpret_as_integer(obj) for obj in (start, stop, step)
)
if step == 0:
raise ValueError('Range() arg 3 must not be zero')
step_sign = int(math.copysign(1, self.step))
self._len = max(
1 + (self.stop - self.start - step_sign) // self.step, 0
)
def __contains__(self, value):
if isinstance(value, numbers.Integral):
return self._index(value) != -1
return any(n == value for n in self)
def __eq__(self, other):
if not isinstance(other, Range):
return False
if self._len != len(other):
return False
if self._len == 0:
return True
if self.start != other.start:
return False
if self[-1] == other[-1]:
return True
return False
def __getitem__(self, index):
if isinstance(index, slice):
start, stop, step = adjust_indices(
self._len, index.start, index.stop, index.step
)
return Range(
self.start + self.step * start,
self.start + self.step * stop,
self.step * step
)
index = interpret_as_integer(index)
if index < 0:
index += self._len
if not 0 <= index < self._len:
raise IndexError('Range object index out of Range')
return self.start + self.step * index
def __hash__(self):
if self._len == 0:
return id(Range)
return hash((self._len, self.start, self[-1]))
def __iter__(self):
value = self.start
if self.step > 0:
while value < self.stop:
yield value
value += self.step
else:
while value > self.stop:
yield value
value += self.step
def __len__(self):
return self._len
def __repr__(self):
if self.step == 1:
return 'Range({}, {})'.format(self.start, self.stop)
return 'Range({}, {}, {})'.format(self.start, self.stop, self.step)
def __reversed__(self):
return iter(self[::-1])
def _index(self, value):
index_mul_step = value - self.start
if index_mul_step % self.step:
return -1
index = index_mul_step // self.step
if 0 <= index < self._len:
return index
return -1
def count(self, value):
"""
Rangeobject.count(value) -> integer
Return number of occurrences of value.
"""
return sum(1 for n in self if n == value)
def index(self, value, start=0, stop=None):
"""
Rangeobject.index(value, [start, [stop]]) -> integer
Return index of value.
Raise ValueError if the value is not present.
"""
if start < 0:
start = max(self._len + start, 0)
if stop is None:
stop = self._len
if stop < 0:
stop += self._len
if isinstance(value, numbers.Integral):
index = self._index(value)
if start <= index < stop:
return index
raise ValueError('{} is not in Range'.format(value))
i = start
n = self.start + self.step * i
while i < stop:
if n == value:
return i
i += 1
n += self.step
raise ValueError('{} is not in Range'.format(value))
collections.abc.Sequence.register(Range)
test_pyrange.py
# pylint: disable = too-few-public-methods
import itertools
from pyrange import Range
class Equal:
def __eq__(self, other):
return True
class Indexable:
def __init__(self, n):
self.n = n
def __index__(self):
return self.n
def test_basic():
small_builtin_range = range(10)
small_my_range = Range(10)
equal = Equal()
assert small_builtin_range.count(equal) == small_my_range.count(equal) == 10
assert small_my_range.index(equal) == small_my_range.index(equal) == 0
big_my_range = Range(0, 10 ** 20, 10 ** 5)
assert 10 ** 15 in big_my_range
assert big_my_range[Indexable(10 ** 3)] == 10 ** 8
assert big_my_range[
Indexable(10 ** 3):Indexable(10 ** 6):Indexable(10 ** 2)
] == Range(10 ** 8, 10 ** 11, 10 ** 7)
def test_slicing():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for slice_start, slice_stop, slice_step in itertools.product(
list(range(-3, 3)) + [None], repeat=3
):
if slice_step == 0:
continue
slc = slice(slice_start, slice_stop, slice_step)
builtin_range_slice = builtin_range[slc]
my_range_slice = my_range[slc]
for name in ('start', 'stop', 'step'):
assert (
getattr(builtin_range_slice, name) ==
getattr(my_range_slice, name)
), (start, stop, step, slice_start, slice_stop, slice_step)
def test_eq_and_hash():
for start, stop, step in itertools.product(range(-3, 3), repeat=3):
if step == 0:
continue
builtin_range = range(start, stop, step)
my_range = Range(start, stop, step)
for start_2, stop_2, step_2 in itertools.product(
range(-3, 3), repeat=3
):
if step_2 == 0:
continue
builtin_range_2 = range(start_2, stop_2, step_2)
my_range_2 = Range(start_2, stop_2, step_2)
if builtin_range == builtin_range_2:
assert my_range == my_range_2, (
start, stop, step, start_2, stop_2, step_2
)
assert hash(my_range) == hash(my_range_2), (
start, stop, step, start_2, stop_2, step_2
)
python reinventing-the-wheel interval
python reinventing-the-wheel interval
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
edited 8 hours ago
dfhwze
11.7k2 gold badges22 silver badges77 bronze badges
11.7k2 gold badges22 silver badges77 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
sanyashsanyash
1364 bronze badges
asked 8 hours ago
sanyashsanyash
1364 bronze badges
1364 bronze badges
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
sanyash is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
Your constructor is__init__(start, stop=None, step=1). Shouldn'tstartbe optional andstoppositional?range(3)means[0, 1, 2], not[3, 4, 5, ...].
$endgroup$
– Jack M
7 hours ago
$begingroup$
@JackM in case ofRange(3)there are linesif stop is None: start, stop = 0, start.
$endgroup$
– sanyash
7 hours ago
add a comment
|
$begingroup$
Your constructor is__init__(start, stop=None, step=1). Shouldn'tstartbe optional andstoppositional?range(3)means[0, 1, 2], not[3, 4, 5, ...].
$endgroup$
– Jack M
7 hours ago
$begingroup$
@JackM in case ofRange(3)there are linesif stop is None: start, stop = 0, start.
$endgroup$
– sanyash
7 hours ago
$begingroup$
Your constructor is
__init__(start, stop=None, step=1). Shouldn't start be optional and stop positional? range(3) means [0, 1, 2], not [3, 4, 5, ...].$endgroup$
– Jack M
7 hours ago
$begingroup$
Your constructor is
__init__(start, stop=None, step=1). Shouldn't start be optional and stop positional? range(3) means [0, 1, 2], not [3, 4, 5, ...].$endgroup$
– Jack M
7 hours ago
$begingroup$
@JackM in case of
Range(3) there are lines if stop is None: start, stop = 0, start.$endgroup$
– sanyash
7 hours ago
$begingroup$
@JackM in case of
Range(3) there are lines if stop is None: start, stop = 0, start.$endgroup$
– sanyash
7 hours ago
add a comment
|
1 Answer
1
active
oldest
votes
1
$begingroup$
It does not mimic all aspects of range. The range object is immutable:
>>> r = range(1,5,2)
>>> r.start
1
>>> r.start = 3
Traceback (most recent call last):
module __main__ line 130
traceback.print_exc()
module <module> line 1
r.start = 3
AttributeError: readonly attribute
>>>
Yours is not. But you might be able to fix that by inheriting from collections.namedtuple.
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
$endgroup$
$begingroup$
Good point about immutability. However I don't think that inhertiting fromcollections.namedtupleis the best idea. Do you know another alternatives?
$endgroup$
– sanyash
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting fromnamedtuple?
$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
Because logicallyRangehas nothing common withnamedtupleortuple.range_obj[0] == range_obj.startbutrange_obj[1] != range_obj.stopin many cases andrange_obj[2] != range_obj.stepin many cases.
$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking__setattr__is the best way.
$endgroup$
– sanyash
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass anamedtupleand overload the__getitem__method to a different behaviour. How ... exceptional. Well, you’ve got the__setattr__hack, so you can make yourRangeimmutable that way.
$endgroup$
– AJNeufeld
3 hours ago
add a comment
|
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "196"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/4.0/"u003ecc by-sa 4.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
sanyash is a new contributor. Be nice, and check out our Code of Conduct.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f229073%2fpure-python-range-implementation%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
1
$begingroup$
It does not mimic all aspects of range. The range object is immutable:
>>> r = range(1,5,2)
>>> r.start
1
>>> r.start = 3
Traceback (most recent call last):
module __main__ line 130
traceback.print_exc()
module <module> line 1
r.start = 3
AttributeError: readonly attribute
>>>
Yours is not. But you might be able to fix that by inheriting from collections.namedtuple.
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
$endgroup$
$begingroup$
Good point about immutability. However I don't think that inhertiting fromcollections.namedtupleis the best idea. Do you know another alternatives?
$endgroup$
– sanyash
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting fromnamedtuple?
$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
Because logicallyRangehas nothing common withnamedtupleortuple.range_obj[0] == range_obj.startbutrange_obj[1] != range_obj.stopin many cases andrange_obj[2] != range_obj.stepin many cases.
$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking__setattr__is the best way.
$endgroup$
– sanyash
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass anamedtupleand overload the__getitem__method to a different behaviour. How ... exceptional. Well, you’ve got the__setattr__hack, so you can make yourRangeimmutable that way.
$endgroup$
– AJNeufeld
3 hours ago
add a comment
|
1
$begingroup$
It does not mimic all aspects of range. The range object is immutable:
>>> r = range(1,5,2)
>>> r.start
1
>>> r.start = 3
Traceback (most recent call last):
module __main__ line 130
traceback.print_exc()
module <module> line 1
r.start = 3
AttributeError: readonly attribute
>>>
Yours is not. But you might be able to fix that by inheriting from collections.namedtuple.
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
$endgroup$
$begingroup$
Good point about immutability. However I don't think that inhertiting fromcollections.namedtupleis the best idea. Do you know another alternatives?
$endgroup$
– sanyash
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting fromnamedtuple?
$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
Because logicallyRangehas nothing common withnamedtupleortuple.range_obj[0] == range_obj.startbutrange_obj[1] != range_obj.stopin many cases andrange_obj[2] != range_obj.stepin many cases.
$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking__setattr__is the best way.
$endgroup$
– sanyash
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass anamedtupleand overload the__getitem__method to a different behaviour. How ... exceptional. Well, you’ve got the__setattr__hack, so you can make yourRangeimmutable that way.
$endgroup$
– AJNeufeld
3 hours ago
add a comment
|
1
1
1
$begingroup$
It does not mimic all aspects of range. The range object is immutable:
>>> r = range(1,5,2)
>>> r.start
1
>>> r.start = 3
Traceback (most recent call last):
module __main__ line 130
traceback.print_exc()
module <module> line 1
r.start = 3
AttributeError: readonly attribute
>>>
Yours is not. But you might be able to fix that by inheriting from collections.namedtuple.
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
$endgroup$
It does not mimic all aspects of range. The range object is immutable:
>>> r = range(1,5,2)
>>> r.start
1
>>> r.start = 3
Traceback (most recent call last):
module __main__ line 130
traceback.print_exc()
module <module> line 1
r.start = 3
AttributeError: readonly attribute
>>>
Yours is not. But you might be able to fix that by inheriting from collections.namedtuple.
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
answered 4 hours ago
AJNeufeldAJNeufeld
12.1k1 gold badge11 silver badges37 bronze badges
12.1k1 gold badge11 silver badges37 bronze badges
$begingroup$
Good point about immutability. However I don't think that inhertiting fromcollections.namedtupleis the best idea. Do you know another alternatives?
$endgroup$
– sanyash
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting fromnamedtuple?
$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
Because logicallyRangehas nothing common withnamedtupleortuple.range_obj[0] == range_obj.startbutrange_obj[1] != range_obj.stopin many cases andrange_obj[2] != range_obj.stepin many cases.
$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking__setattr__is the best way.
$endgroup$
– sanyash
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass anamedtupleand overload the__getitem__method to a different behaviour. How ... exceptional. Well, you’ve got the__setattr__hack, so you can make yourRangeimmutable that way.
$endgroup$
– AJNeufeld
3 hours ago
add a comment
|
$begingroup$
Good point about immutability. However I don't think that inhertiting fromcollections.namedtupleis the best idea. Do you know another alternatives?
$endgroup$
– sanyash
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting fromnamedtuple?
$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
Because logicallyRangehas nothing common withnamedtupleortuple.range_obj[0] == range_obj.startbutrange_obj[1] != range_obj.stopin many cases andrange_obj[2] != range_obj.stepin many cases.
$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking__setattr__is the best way.
$endgroup$
– sanyash
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass anamedtupleand overload the__getitem__method to a different behaviour. How ... exceptional. Well, you’ve got the__setattr__hack, so you can make yourRangeimmutable that way.
$endgroup$
– AJNeufeld
3 hours ago
$begingroup$
Good point about immutability. However I don't think that inhertiting from
collections.namedtuple is the best idea. Do you know another alternatives?$endgroup$
– sanyash
4 hours ago
$begingroup$
Good point about immutability. However I don't think that inhertiting from
collections.namedtuple is the best idea. Do you know another alternatives?$endgroup$
– sanyash
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting from
namedtuple?$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
The are hacks to make objects immutable, such as here and here, but why are you opposed to inheriting from
namedtuple?$endgroup$
– AJNeufeld
4 hours ago
$begingroup$
Because logically
Range has nothing common with namedtuple or tuple. range_obj[0] == range_obj.start but range_obj[1] != range_obj.stop in many cases and range_obj[2] != range_obj.step in many cases.$endgroup$
– sanyash
3 hours ago
$begingroup$
Because logically
Range has nothing common with namedtuple or tuple. range_obj[0] == range_obj.start but range_obj[1] != range_obj.stop in many cases and range_obj[2] != range_obj.step in many cases.$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking
__setattr__ is the best way.$endgroup$
– sanyash
3 hours ago
$begingroup$
As I see, hacking
__setattr__ is the best way.$endgroup$
– sanyash
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass a
namedtuple and overload the __getitem__ method to a different behaviour. How ... exceptional. Well, you’ve got the __setattr__ hack, so you can make your Range immutable that way.$endgroup$
– AJNeufeld
3 hours ago
$begingroup$
Hmm. It seems I can’t subclass a
namedtuple and overload the __getitem__ method to a different behaviour. How ... exceptional. Well, you’ve got the __setattr__ hack, so you can make your Range immutable that way.$endgroup$
– AJNeufeld
3 hours ago
add a comment
|
sanyash is a new contributor. Be nice, and check out our Code of Conduct.
draft saved
draft discarded
sanyash is a new contributor. Be nice, and check out our Code of Conduct.
sanyash is a new contributor. Be nice, and check out our Code of Conduct.
sanyash is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Code Review Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f229073%2fpure-python-range-implementation%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
$begingroup$
Your constructor is
__init__(start, stop=None, step=1). Shouldn'tstartbe optional andstoppositional?range(3)means[0, 1, 2], not[3, 4, 5, ...].$endgroup$
– Jack M
7 hours ago
$begingroup$
@JackM in case of
Range(3)there are linesif stop is None: start, stop = 0, start.$endgroup$
– sanyash
7 hours ago