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1 11 aaronmk
# Useful functions and classes
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#### Object metadata
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def type_name(value): return type(value).__name__
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def module(value): return type(value).__module__.split('.')
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def root_module(value): return module(value)[0]
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#### Basic types
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class ConstraintError(ValueError):
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    def __init__(self, check_func, value):
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        ValueError.__init__(self, str(value)+' must satisfy constraint '
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            +check_func.__name__)
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def is_str(val): return isinstance(val, basestring)
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#### Iterables
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def first(iter_): return iter_.next()
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def skip(iter_, func):
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    # Advance iter while func is True
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    try:
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        while func(iter_.curr()): iter_.next()
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    except StopIteration: pass # nothing after the matching elements
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class CheckedIter:
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    def __init__(self, check_func, iterable):
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        self.check_func = check_func
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        self.iter_ = iterable.__iter__()
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    def __iter__(self): return self
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    def next(self):
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        entry = self.iter_.next()
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        if self.check_func(entry): return entry
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        else: raise ConstraintError(self.check_func, entry)
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#### Dicts
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def rename_key(dict_, orig, new): dict_[new] = dict_.pop(orig)
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def dict_subset(dict_, keys):
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    subset = dict()
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    for key in keys:
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        try: subset[key] = dict_[key]
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        except KeyError: pass
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    return subset