mirror of
https://github.com/wassname/catalyst.git
synced 2026-07-01 04:48:39 +08:00
Scott Sanderson
657a132f1e
We rely on these upstream, for better or worse, so add tests and docs. Also adds distinct `EquitiesNotFound` and `FutureContractsNotFound` exceptions.
74 lines
1.6 KiB
Python
74 lines
1.6 KiB
Python
"""
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Control flow utilities.
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"""
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from six import iteritems
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from warnings import (
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catch_warnings,
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filterwarnings,
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)
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class nullctx(object):
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"""
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Null context manager. Useful for conditionally adding a contextmanager in
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a single line, e.g.:
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with SomeContextManager() if some_expr else nullctx():
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do_stuff()
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"""
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def __enter__(self):
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return self
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def __exit__(*args):
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return False
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class WarningContext(object):
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"""
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Re-entrant contextmanager for contextually managing warnings.
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"""
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def __init__(self, *warning_specs):
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self._warning_specs = warning_specs
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self._catchers = []
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def __enter__(self):
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catcher = catch_warnings()
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catcher.__enter__()
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self._catchers.append(catcher)
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for args, kwargs in self._warning_specs:
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filterwarnings(*args, **kwargs)
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return catcher
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def __exit__(self, *exc_info):
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catcher = self._catchers.pop()
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return catcher.__exit__(*exc_info)
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def ignore_nanwarnings():
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"""
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Helper for building a WarningContext that ignores warnings from numpy's
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nanfunctions.
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"""
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return WarningContext(
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(
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('ignore',),
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{'category': RuntimeWarning, 'module': 'numpy.lib.nanfunctions'},
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)
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)
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def invert(d):
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"""
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Invert a dictionary into a dictionary of sets.
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>>> invert({'a': 1, 'b': 2, 'c': 1})
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{1: {'a', 'c'}, 2: {'b'}}
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"""
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out = {}
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for k, v in iteritems(d):
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try:
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out[v].add(k)
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except KeyError:
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out[v] = {k}
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return out
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