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# -*- coding: utf-8 -*- |
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"""Common collection classes.""" |
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from __future__ import print_function, division, absolute_import |
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from functools import reduce |
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from .compat import text_type |
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# http://stackoverflow.com/a/14620633/2127762 |
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class AttrDict(dict): |
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"""Sub-classes dict, and further allows attribute-like access to dictionary items. |
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Examples: |
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>>> d = AttrDict({'a': 1}) |
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>>> d.a, d['a'], d.get('a') |
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(1, 1, 1) |
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>>> d.b = 2 |
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>>> d.b, d['b'] |
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(2, 2) |
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""" |
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def __init__(self, *args, **kwargs): |
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super(AttrDict, self).__init__(*args, **kwargs) |
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self.__dict__ = self |
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class frozendict(dict): |
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def __key(self): |
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return tuple((k, self[k]) for k in sorted(self)) |
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def __hash__(self): |
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return hash(self.__key()) |
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def __eq__(self, other): |
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return self.__key() == other.__key() |
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def first(seq, key=lambda x: bool(x), default=None, apply=lambda x: x): |
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"""Give the first value that satisfies the key test. |
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Args: |
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seq (iterable): |
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key (callable): test for each element of iterable |
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default: returned when all elements fail test |
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apply (callable): applied to element before return |
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Returns: first element in seq that passes key, mutated with optional apply |
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Examples: |
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>>> first([0, False, None, [], (), 42]) |
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42 |
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>>> first([0, False, None, [], ()]) is None |
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True |
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>>> first([0, False, None, [], ()], default='ohai') |
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'ohai' |
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>>> import re |
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>>> m = first(re.match(regex, 'abc') for regex in ['b.*', 'a(.*)']) |
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>>> m.group(1) |
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'bc' |
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The optional `key` argument specifies a one-argument predicate function |
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like that used for `filter()`. The `key` argument, if supplied, must be |
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in keyword form. For example: |
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>>> first([1, 1, 3, 4, 5], key=lambda x: x % 2 == 0) |
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4 |
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""" |
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return next((apply(x) for x in seq if key(x)), default) |
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def firstitem(map, key=lambda k, v: bool(k), default=None, apply=lambda k, v: (k, v)): |
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return next((apply(k, v) for k, v in map if key(k, v)), default) |
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def last(seq, key=lambda x: bool(x), default=None, apply=lambda x: x): |
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return next((apply(x) for x in reversed(seq) if key(x)), default) |
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def call_each(seq): |
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"""Calls each element of sequence to invoke the side effect. |
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Args: |
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seq: |
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Returns: None |
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""" |
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try: |
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reduce(lambda _, y: y(), seq) |
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except TypeError as e: |
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if text_type(e) != "reduce() of empty sequence with no initial value": |
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raise |
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kalefranz /
auxlib
