"""
Utility functions.
.. versionadded:: 1.0.0
"""
from collections import namedtuple
from datetime import datetime
from functools import partial, wraps
import math
from random import randint, uniform
import re
import time
import pydash as pyd
from .helpers import NUMBER_TYPES, UNSET, base_get, callit, getargcount, iterator
__all__ = (
"attempt",
"cond",
"conforms",
"conforms_to",
"constant",
"default_to",
"default_to_any",
"identity",
"iteratee",
"matches",
"matches_property",
"memoize",
"method",
"method_of",
"noop",
"nth_arg",
"now",
"over",
"over_every",
"over_some",
"properties",
"property_",
"property_of",
"random",
"range_",
"range_right",
"result",
"retry",
"stub_list",
"stub_dict",
"stub_false",
"stub_string",
"stub_true",
"times",
"to_path",
"unique_id",
)
# These regexes are used in to_path() to parse deep path strings.
# This is used to split a deep path string into dict keys or list indexes. This matches "." as
# delimiter (unless it is escaped by "//") and "[<integer>]" as delimiter while keeping the
# "[<integer>]" as an item.
RE_PATH_KEY_DELIM = re.compile(r"(?<!\\)(?:\\\\)*\.|(\[\d+\])")
# Matches on path strings like "[<integer>]". This is used to test whether a path string part is a
# list index.
RE_PATH_LIST_INDEX = re.compile(r"^\[\d+\]$")
ID_COUNTER = 0
PathToken = namedtuple("PathToken", ["key", "default_factory"])
[docs]
def attempt(func, *args, **kwargs):
"""
Attempts to execute `func`, returning either the result or the caught error object.
Args:
func (callable): The function to attempt.
Returns:
mixed: Returns the `func` result or error object.
Example:
>>> results = attempt(lambda x: x/0, 1)
>>> assert isinstance(results, ZeroDivisionError)
.. versionadded:: 1.1.0
"""
try:
ret = func(*args, **kwargs)
except Exception as ex:
ret = ex
return ret
[docs]
def cond(pairs, *extra_pairs):
"""
Creates a function that iterates over `pairs` and invokes the corresponding function of the
first predicate to return truthy.
Args:
pairs (list): A list of predicate-function pairs.
Returns:
callable: Returns the new composite function.
Example:
>>> func = cond([[matches({'a': 1}), constant('matches A')],\
[matches({'b': 2}), constant('matches B')],\
[stub_true, lambda value: value]])
>>> func({'a': 1, 'b': 2})
'matches A'
>>> func({'a': 0, 'b': 2})
'matches B'
>>> func({'a': 0, 'b': 0}) == {'a': 0, 'b': 0}
True
.. versionadded:: 4.0.0
.. versionchanged:: 4.2.0
Fixed missing argument passing to matched function and added support for passing in a single
list of pairs instead of just pairs as separate arguments.
"""
if extra_pairs:
pairs = [pairs] + list(extra_pairs)
for pair in pairs:
is_valid = False
try:
is_valid = len(pair) == 2
except Exception:
pass
if not is_valid:
raise ValueError("Each predicate-function pair should contain " "exactly two elements")
if not all(map(callable, pair)):
raise TypeError("Both predicate-function pair should be callable")
def _cond(*args):
for pair in pairs:
predicate, iteratee = pair
if callit(predicate, *args):
return iteratee(*args)
return _cond
[docs]
def constant(value):
"""
Creates a function that returns `value`.
Args:
value (mixed): Constant value to return.
Returns:
callable: Function that always returns `value`.
Example:
>>> pi = constant(3.14)
>>> pi() == 3.14
True
.. versionadded:: 1.0.0
.. versionchanged:: 4.0.0
Returned function ignores arguments instead of raising exception.
"""
return partial(identity, value)
[docs]
def default_to(value, default_value):
"""
Checks `value` to determine whether a default value should be returned in its place. The
`default_value` is returned if value is None.
Args:
value (mixed): Value passed in by the user.
default_value (mixed): Default value passed in by the user.
Returns:
mixed: Returns `value` if :attr:`value` is given otherwise returns `default_value`.
Example:
>>> default_to(1, 10)
1
>>> default_to(None, 10)
10
.. versionadded:: 4.0.0
"""
return default_to_any(value, default_value)
[docs]
def default_to_any(value, *default_values):
"""
Checks `value` to determine whether a default value should be returned in its place. The first
item that is not None of the `default_values` is returned.
Args:
value (mixed): Value passed in by the user.
*default_values (mixed): Default values passed in by the user.
Returns:
mixed: Returns `value` if :attr:`value` is given otherwise returns the first not None value
of `default_values`.
Example:
>>> default_to_any(1, 10, 20)
1
>>> default_to_any(None, 10, 20)
10
>>> default_to_any(None, None, 20)
20
.. versionadded:: 4.9.0
"""
values = (value,) + default_values
for val in values:
if val is not None:
return val
[docs]
def identity(arg=None, *args):
"""
Return the first argument provided to it.
Args:
*args (mixed): Arguments.
Returns:
mixed: First argument or ``None``.
Example:
>>> identity(1)
1
>>> identity(1, 2, 3)
1
>>> identity() is None
True
.. versionadded:: 1.0.0
"""
return arg
[docs]
def iteratee(func):
"""
Return a pydash style iteratee. If `func` is a property name the created iteratee will return
the property value for a given element. If `func` is an object the created iteratee will return
``True`` for elements that contain the equivalent object properties, otherwise it will return
``False``.
Args:
func (mixed): Object to create iteratee function from.
Returns:
callable: Iteratee function.
Example:
>>> get_data = iteratee('data')
>>> get_data({'data': [1, 2, 3]})
[1, 2, 3]
>>> is_active = iteratee({'active': True})
>>> is_active({'active': True})
True
>>> is_active({'active': 0})
False
>>> iteratee(['a', 5])({'a': 5})
True
>>> iteratee(['a.b'])({'a.b': 5})
5
>>> iteratee('a.b')({'a': {'b': 5}})
5
>>> iteratee(('a', ['c', 'd', 'e']))({'a': 1, 'c': {'d': {'e': 3}}})
[1, 3]
>>> iteratee(lambda a, b: a + b)(1, 2)
3
>>> ident = iteratee(None)
>>> ident('a')
'a'
>>> ident(1, 2, 3)
1
.. versionadded:: 1.0.0
.. versionchanged:: 2.0.0
Renamed ``create_iteratee()`` to :func:`iteratee`.
.. versionchanged:: 3.0.0
Made pluck style iteratee support deep property access.
.. versionchanged:: 3.1.0
- Added support for shallow pluck style property access via single item list/tuple.
- Added support for matches property style iteratee via two item list/tuple.
.. versionchanged:: 4.0.0
Removed alias ``callback``.
.. versionchanged:: 4.1.0
Return :func:`properties` callback when `func` is a ``tuple``.
"""
if callable(func):
cbk = func
else:
if isinstance(func, int):
func = str(func)
if isinstance(func, str):
cbk = property_(func)
elif isinstance(func, list) and len(func) == 1:
cbk = property_(func)
elif isinstance(func, list) and len(func) > 1:
cbk = matches_property(*func[:2])
elif isinstance(func, tuple):
cbk = properties(*func)
elif isinstance(func, dict):
cbk = matches(func)
else:
cbk = identity
# Optimize iteratee by specifying the exact number of arguments the iteratee takes so that
# arg inspection (costly process) can be skipped in helpers.callit().
cbk._argcount = 1
return cbk
[docs]
def matches(source):
"""
Creates a matches-style predicate function which performs a deep comparison between a given
object and the `source` object, returning ``True`` if the given object has equivalent property
values, else ``False``.
Args:
source (dict): Source object used for comparision.
Returns:
callable: Function that compares an object to `source` and returns whether the two objects
contain the same items.
Example:
>>> matches({'a': {'b': 2}})({'a': {'b': 2, 'c':3}})
True
>>> matches({'a': 1})({'b': 2, 'a': 1})
True
>>> matches({'a': 1})({'b': 2, 'a': 2})
False
.. versionadded:: 1.0.0
.. versionchanged:: 3.0.0
Use :func:`pydash.predicates.is_match` as matching function.
"""
return lambda obj: pyd.is_match(obj, source)
[docs]
def matches_property(key, value):
"""
Creates a function that compares the property value of `key` on a given object to `value`.
Args:
key (str): Object key to match against.
value (mixed): Value to compare to.
Returns:
callable: Function that compares `value` to an object's `key` and returns whether they are
equal.
Example:
>>> matches_property('a', 1)({'a': 1, 'b': 2})
True
>>> matches_property(0, 1)([1, 2, 3])
True
>>> matches_property('a', 2)({'a': 1, 'b': 2})
False
.. versionadded:: 3.1.0
"""
prop_accessor = property_(key)
return lambda obj: matches(value)(prop_accessor(obj))
[docs]
def memoize(func, resolver=None):
"""
Creates a function that memoizes the result of `func`. If `resolver` is provided it will be used
to determine the cache key for storing the result based on the arguments provided to the
memoized function. By default, all arguments provided to the memoized function are used as the
cache key. The result cache is exposed as the cache property on the memoized function.
Args:
func (callable): Function to memoize.
resolver (callable, optional): Function that returns the cache key to use.
Returns:
callable: Memoized function.
Example:
>>> ident = memoize(identity)
>>> ident(1)
1
>>> ident.cache['(1,){}'] == 1
True
>>> ident(1, 2, 3)
1
>>> ident.cache['(1, 2, 3){}'] == 1
True
.. versionadded:: 1.0.0
"""
def memoized(*args, **kwargs):
if resolver:
key = resolver(*args, **kwargs)
else:
key = f"{args}{kwargs}"
if key not in memoized.cache:
memoized.cache[key] = func(*args, **kwargs)
return memoized.cache[key]
memoized.cache = {}
return memoized
[docs]
def method(path, *args, **kwargs):
"""
Creates a function that invokes the method at `path` on a given object. Any additional arguments
are provided to the invoked method.
Args:
path (str): Object path of method to invoke.
*args (mixed): Global arguments to apply to method when invoked.
**kwargs (mixed): Global keyword argument to apply to method when invoked.
Returns:
callable: Function that invokes method located at path for object.
Example:
>>> obj = {'a': {'b': [None, lambda x: x]}}
>>> echo = method('a.b.1')
>>> echo(obj, 1) == 1
True
>>> echo(obj, 'one') == 'one'
True
.. versionadded:: 3.3.0
"""
def _method(obj, *_args, **_kwargs):
func = pyd.partial(pyd.get(obj, path), *args, **kwargs)
return func(*_args, **_kwargs)
return _method
[docs]
def method_of(obj, *args, **kwargs):
"""
The opposite of :func:`method`. This method creates a function that invokes the method at a
given path on object. Any additional arguments are provided to the invoked method.
Args:
obj (mixed): The object to query.
*args (mixed): Global arguments to apply to method when invoked.
**kwargs (mixed): Global keyword argument to apply to method when invoked.
Returns:
callable: Function that invokes method located at path for object.
Example:
>>> obj = {'a': {'b': [None, lambda x: x]}}
>>> dispatch = method_of(obj)
>>> dispatch('a.b.1', 1) == 1
True
>>> dispatch('a.b.1', 'one') == 'one'
True
.. versionadded:: 3.3.0
"""
def _method_of(path, *_args, **_kwargs):
func = pyd.partial(pyd.get(obj, path), *args, **kwargs)
return func(*_args, **_kwargs)
return _method_of
[docs]
def noop(*args, **kwargs): # pylint: disable=unused-argument
"""
A no-operation function.
.. versionadded:: 1.0.0
"""
pass
[docs]
def nth_arg(pos=0):
"""
Creates a function that gets the argument at index n. If n is negative, the nth argument from
the end is returned.
Args:
pos (int): The index of the argument to return.
Returns:
callable: Returns the new pass-thru function.
Example:
>>> func = nth_arg(1)
>>> func(11, 22, 33, 44)
22
>>> func = nth_arg(-1)
>>> func(11, 22, 33, 44)
44
.. versionadded:: 4.0.0
"""
def _nth_arg(*args):
try:
position = math.ceil(float(pos))
except ValueError:
position = 0
return pyd.get(args, position)
return _nth_arg
[docs]
def now():
"""
Return the number of milliseconds that have elapsed since the Unix epoch (1 January 1970
00:00:00 UTC).
Returns:
int: Milliseconds since Unix epoch.
.. versionadded:: 1.0.0
.. versionchanged:: 3.0.0
Use ``datetime`` module for calculating elapsed time.
"""
epoch = datetime.utcfromtimestamp(0)
delta = datetime.utcnow() - epoch
if hasattr(delta, "total_seconds"):
seconds = delta.total_seconds()
else: # pragma: no cover
# PY26
seconds = (
delta.microseconds + (delta.seconds + delta.days * 24 * 3600) * 10**6
) / 10**6
return int(seconds * 1000)
[docs]
def over(funcs):
"""
Creates a function that invokes all functions in `funcs` with the arguments it receives and
returns their results.
Args:
funcs (list): List of functions to be invoked.
Returns:
callable: Returns the new pass-thru function.
Example:
>>> func = over([max, min])
>>> func(1, 2, 3, 4)
[4, 1]
.. versionadded:: 4.0.0
"""
def _over(*args):
return [func(*args) for func in funcs]
return _over
[docs]
def over_every(funcs):
"""
Creates a function that checks if all of the functions in `funcs` return truthy when invoked
with the arguments it receives.
Args:
funcs (list): List of functions to be invoked.
Returns:
callable: Returns the new pass-thru function.
Example:
>>> func = over_every([bool, lambda x: x is not None])
>>> func(1)
True
.. versionadded:: 4.0.0
"""
def _over_every(*args):
return all(func(*args) for func in funcs)
return _over_every
[docs]
def over_some(funcs):
"""
Creates a function that checks if any of the functions in `funcs` return truthy when invoked
with the arguments it receives.
Args:
funcs (list): List of functions to be invoked.
Returns:
callable: Returns the new pass-thru function.
Example:
>>> func = over_some([bool, lambda x: x is None])
>>> func(1)
True
.. versionadded:: 4.0.0
"""
def _over_some(*args):
return any(func(*args) for func in funcs)
return _over_some
[docs]
def property_(path):
"""
Creates a function that returns the value at path of a given object.
Args:
path (str|list): Path value to fetch from object.
Returns:
callable: Function that returns object's path value.
Example:
>>> get_data = property_('data')
>>> get_data({'data': 1})
1
>>> get_data({}) is None
True
>>> get_first = property_(0)
>>> get_first([1, 2, 3])
1
.. versionadded:: 1.0.0
.. versionchanged:: 4.0.1
Made property accessor work with deep path strings.
"""
return lambda obj: pyd.get(obj, path)
[docs]
def properties(*paths):
"""
Like :func:`property_` except that it returns a list of values at each path in `paths`.
Args:
*path (str|list): Path values to fetch from object.
Returns:
callable: Function that returns object's path value.
Example:
>>> getter = properties('a', 'b', ['c', 'd', 'e'])
>>> getter({'a': 1, 'b': 2, 'c': {'d': {'e': 3}}})
[1, 2, 3]
.. versionadded:: 4.1.0
"""
return lambda obj: [getter(obj) for getter in (pyd.property_(path) for path in paths)]
[docs]
def property_of(obj):
"""
The inverse of :func:`property_`. This method creates a function that returns the key value of a
given key on `obj`.
Args:
obj (dict|list): Object to fetch values from.
Returns:
callable: Function that returns object's key value.
Example:
>>> getter = property_of({'a': 1, 'b': 2, 'c': 3})
>>> getter('a')
1
>>> getter('b')
2
>>> getter('x') is None
True
.. versionadded:: 3.0.0
.. versionchanged:: 4.0.0
Removed alias ``prop_of``.
"""
return lambda key: pyd.get(obj, key)
[docs]
def random(start=0, stop=1, floating=False):
"""
Produces a random number between `start` and `stop` (inclusive). If only one argument is
provided a number between 0 and the given number will be returned. If floating is truthy or
either `start` or `stop` are floats a floating-point number will be returned instead of an
integer.
Args:
start (int): Minimum value.
stop (int): Maximum value.
floating (bool, optional): Whether to force random value to ``float``. Defaults to
``False``.
Returns:
int|float: Random value.
Example:
>>> 0 <= random() <= 1
True
>>> 5 <= random(5, 10) <= 10
True
>>> isinstance(random(floating=True), float)
True
.. versionadded:: 1.0.0
"""
floating = isinstance(start, float) or isinstance(stop, float) or floating is True
if stop < start:
stop, start = start, stop
if floating:
rnd = uniform(start, stop)
else:
rnd = randint(start, stop)
return rnd
[docs]
def range_(*args):
"""
Creates a list of numbers (positive and/or negative) progressing from start up to but not
including end. If `start` is less than `stop`, a zero-length range is created unless a negative
`step` is specified.
Args:
start (int, optional): Integer to start with. Defaults to ``0``.
stop (int): Integer to stop at.
step (int, optional): The value to increment or decrement by. Defaults to ``1``.
Yields:
int: Next integer in range.
Example:
>>> list(range_(5))
[0, 1, 2, 3, 4]
>>> list(range_(1, 4))
[1, 2, 3]
>>> list(range_(0, 6, 2))
[0, 2, 4]
>>> list(range_(4, 1))
[4, 3, 2]
.. versionadded:: 1.0.0
.. versionchanged:: 1.1.0
Moved to :mod:`pydash.uilities`.
.. versionchanged:: 3.0.0
Return generator instead of list.
.. versionchanged:: 4.0.0
Support decrementing when start argument is greater than stop argument.
"""
return base_range(*args)
[docs]
def range_right(*args):
"""
Similar to :func:`range_`, except that it populates the values in descending order.
Args:
start (int, optional): Integer to start with. Defaults to ``0``.
stop (int): Integer to stop at.
step (int, optional): The value to increment or decrement by. Defaults to ``1`` if `start`
< `stop` else ``-1``.
Yields:
int: Next integer in range.
Example:
>>> list(range_right(5))
[4, 3, 2, 1, 0]
>>> list(range_right(1, 4))
[3, 2, 1]
>>> list(range_right(0, 6, 2))
[4, 2, 0]
.. versionadded:: 4.0.0
"""
return base_range(*args, from_right=True)
[docs]
def result(obj, key, default=None):
"""
Return the value of property `key` on `obj`. If `key` value is a function it will be invoked and
its result returned, else the property value is returned. If `obj` is falsey then `default` is
returned.
Args:
obj (list|dict): Object to retrieve result from.
key (mixed): Key or index to get result from.
default (mixed, optional): Default value to return if `obj` is falsey. Defaults to ``None``.
Returns:
mixed: Result of ``obj[key]`` or ``None``.
Example:
>>> result({'a': 1, 'b': lambda: 2}, 'a')
1
>>> result({'a': 1, 'b': lambda: 2}, 'b')
2
>>> result({'a': 1, 'b': lambda: 2}, 'c') is None
True
>>> result({'a': 1, 'b': lambda: 2}, 'c', default=False)
False
.. versionadded:: 1.0.0
.. versionchanged:: 2.0.0
Added ``default`` argument.
"""
if not obj:
return default
ret = base_get(obj, key, default=default)
if callable(ret):
ret = ret()
return ret
[docs]
def retry( # noqa: C901
attempts=3,
delay=0.5,
max_delay=150.0,
scale=2.0,
jitter=0,
exceptions=(Exception,),
on_exception=None,
):
"""
Decorator that retries a function multiple times if it raises an exception with an optional
delay between each attempt.
When a `delay` is supplied, there will be a sleep period in between retry
attempts. The first delay time will always be equal to `delay`. After
subsequent retries, the delay time will be scaled by `scale` up to
`max_delay`. If `max_delay` is ``0``, then `delay` can increase unbounded.
Args:
attempts (int, optional): Number of retry attempts. Defaults to ``3``.
delay (int|float, optional): Base amount of seconds to sleep between retry attempts.
Defaults to ``0.5``.
max_delay (int|float, optional): Maximum number of seconds to sleep between retries. Is
ignored when equal to ``0``. Defaults to ``150.0`` (2.5 minutes).
scale (int|float, optional): Scale factor to increase `delay` after first retry fails.
Defaults to ``2.0``.
jitter (int|float|tuple, optional): Random jitter to add to `delay` time. Can be a positive
number or 2-item tuple of numbers representing the random range to choose from. When a
number is given, the random range will be from ``[0, jitter]``. When jitter is a float
or contains a float, then a random float will be chosen; otherwise, a random integer
will be selected. Defaults to ``0`` which disables jitter.
exceptions (tuple, optional): Tuple of exceptions that trigger a retry attempt. Exceptions
not in the tuple will be ignored. Defaults to ``(Exception,)`` (all exceptions).
on_exception (callable, optional): Function that is called when a retryable exception is
caught. It is invoked with ``on_exception(exc, attempt)`` where ``exc`` is the caught
exception and ``attempt`` is the attempt count. All arguments are optional. Defaults to
``None``.
Example:
>>> @retry(attempts=3, delay=0)
... def do_something():
... print('something')
... raise Exception('something went wrong')
>>> try: do_something()
... except Exception: print('caught something')
something
something
something
caught something
..versionadded:: 4.4.0
..versionchanged:: 4.5.0
Added ``jitter`` argument.
"""
if not isinstance(attempts, int) or attempts <= 0:
raise ValueError("attempts must be an integer greater than 0")
if not isinstance(delay, NUMBER_TYPES) or delay < 0:
raise ValueError("delay must be a number greater than or equal to 0")
if not isinstance(max_delay, NUMBER_TYPES) or max_delay < 0:
raise ValueError("scale must be a number greater than or equal to 0")
if not isinstance(scale, NUMBER_TYPES) or scale <= 0:
raise ValueError("scale must be a number greater than 0")
if (
not isinstance(jitter, NUMBER_TYPES + (tuple,))
or (isinstance(jitter, NUMBER_TYPES) and jitter < 0)
or (
isinstance(jitter, tuple)
and (len(jitter) != 2 or not all(isinstance(jit, NUMBER_TYPES) for jit in jitter))
)
):
raise ValueError("jitter must be a number greater than 0 or a 2-item tuple of " "numbers")
if not isinstance(exceptions, tuple) or not all(
issubclass(exc, Exception) for exc in exceptions
):
raise TypeError("exceptions must be a tuple of Exception types")
if on_exception and not callable(on_exception):
raise TypeError("on_exception must be a callable")
if jitter and not isinstance(jitter, tuple):
jitter = (0, jitter)
on_exc_argcount = getargcount(on_exception, maxargs=2) if on_exception else None
def decorator(func):
@wraps(func)
def decorated(*args, **kwargs):
delay_time = delay
for attempt in range(1, attempts + 1):
# pylint: disable=catching-non-exception
try:
return func(*args, **kwargs)
except exceptions as exc:
if on_exception:
callit(on_exception, exc, attempt, argcount=on_exc_argcount)
if attempt == attempts:
raise
if jitter:
delay_time += max(0, random(*jitter))
if delay_time < 0: # pragma: no cover
continue
if max_delay:
delay_time = min(delay_time, max_delay)
time.sleep(delay_time)
# Scale after first iteration.
delay_time *= scale
return decorated
return decorator
[docs]
def stub_list():
"""
Returns empty "list".
Returns:
list: Empty list.
Example:
>>> stub_list()
[]
.. versionadded:: 4.0.0
"""
return []
[docs]
def stub_dict():
"""
Returns empty "dict".
Returns:
dict: Empty dict.
Example:
>>> stub_dict()
{}
.. versionadded:: 4.0.0
"""
return {}
[docs]
def stub_false():
"""
Returns ``False``.
Returns:
bool: False
Example:
>>> stub_false()
False
.. versionadded:: 4.0.0
"""
return False
[docs]
def stub_string():
"""
Returns an empty string.
Returns:
str: Empty string
Example:
>>> stub_string()
''
.. versionadded:: 4.0.0
"""
return ""
[docs]
def stub_true():
"""
Returns ``True``.
Returns:
bool: True
Example:
>>> stub_true()
True
.. versionadded:: 4.0.0
"""
return True
[docs]
def times(n, iteratee=None):
"""
Executes the iteratee `n` times, returning a list of the results of each iteratee execution. The
iteratee is invoked with one argument: ``(index)``.
Args:
n (int): Number of times to execute `iteratee`.
iteratee (callable): Function to execute.
Returns:
list: A list of results from calling `iteratee`.
Example:
>>> times(5, lambda i: i)
[0, 1, 2, 3, 4]
.. versionadded:: 1.0.0
.. versionchanged:: 3.0.0
Reordered arguments to make `iteratee` first.
.. versionchanged:: 4.0.0
- Re-reordered arguments to make `iteratee` last argument.
- Added functionality for handling `iteratee` with zero positional arguments.
"""
if iteratee is None:
iteratee = identity
argcount = 1
else:
argcount = getargcount(iteratee, maxargs=1)
return [callit(iteratee, index, argcount=argcount) for index in range(n)]
[docs]
def to_path(value):
"""
Converts values to a property path array.
Args:
value (mixed): Value to convert.
Returns:
list: Returns the new property path array.
Example:
>>> to_path('a.b.c')
['a', 'b', 'c']
>>> to_path('a[0].b.c')
['a', 0, 'b', 'c']
>>> to_path('a[0][1][2].b.c')
['a', 0, 1, 2, 'b', 'c']
.. versionadded:: 4.0.0
.. versionchanged:: 4.2.1
Ensure returned path is always a list.
"""
tokens = to_path_tokens(value)
if isinstance(tokens, list):
path = [
token.key if isinstance(token, PathToken) else token for token in to_path_tokens(value)
]
else:
path = [tokens]
return path
[docs]
def unique_id(prefix=None):
"""
Generates a unique ID. If `prefix` is provided the ID will be appended to it.
Args:
prefix (str, optional): String prefix to prepend to ID value.
Returns:
str: ID value.
Example:
>>> unique_id()
'1'
>>> unique_id('id_')
'id_2'
>>> unique_id()
'3'
.. versionadded:: 1.0.0
"""
# pylint: disable=global-statement
global ID_COUNTER
ID_COUNTER += 1
if prefix is None:
prefix = ""
else:
prefix = pyd.to_string(prefix)
return f"{prefix}{ID_COUNTER}"
#
# Helper functions not a part of main API
#
def to_path_tokens(value):
"""Parse `value` into :class:`PathToken` objects."""
if pyd.is_string(value) and ("." in value or "[" in value):
# Since we can't tell whether a bare number is supposed to be dict key or a list index, we
# support a special syntax where any string-integer surrounded by brackets is treated as a
# list index and converted to an integer.
keys = [
PathToken(int(key[1:-1]), default_factory=list)
if RE_PATH_LIST_INDEX.match(key)
else PathToken(unescape_path_key(key), default_factory=dict)
for key in filter(None, RE_PATH_KEY_DELIM.split(value))
]
elif pyd.is_string(value) or pyd.is_number(value):
keys = [PathToken(value, default_factory=dict)]
elif value is UNSET:
keys = []
else:
keys = value
return keys
def unescape_path_key(key):
"""Unescape path key."""
key = key.replace(r"\\", "\\")
key = key.replace(r"\.", r".")
return key
def base_range(*args, **kwargs):
"""Yield range values."""
from_right = kwargs.get("from_right", False)
if len(args) >= 3:
args = args[:3]
elif len(args) == 2:
args = (args[0], args[1], None)
elif len(args) == 1:
args = (0, args[0], None)
if args and args[2] is None:
check_args = args[:2]
else:
check_args = args
for arg in check_args:
if not isinstance(arg, int): # pragma: no cover
raise TypeError(f"range cannot interpret {type(arg).__name__!r} object as an integer")
def gen():
if not args:
return
start, stop, step = args
if step is None:
step = 1 if start < stop else -1
length = int(max([math.ceil((stop - start) / (step or 1)), 0]))
if from_right:
start += (step * length) - step
step *= -1
while length:
yield start
start += step
length -= 1
return gen()