| 1 |
11
|
aaronmk
|
# Useful functions and classes
|
| 2 |
|
|
|
| 3 |
1068
|
aaronmk
|
import collections
|
| 4 |
|
|
|
| 5 |
931
|
aaronmk
|
#### Function wrappers for statements
|
| 6 |
|
|
|
| 7 |
|
|
def noop(*args, **kw_args): pass
|
| 8 |
|
|
|
| 9 |
|
|
def and_(a, b): return a and b
|
| 10 |
|
|
|
| 11 |
791
|
aaronmk
|
#### Object metadata
|
| 12 |
|
|
|
| 13 |
341
|
aaronmk
|
def type_name(value): return type(value).__name__
|
| 14 |
|
|
|
| 15 |
135
|
aaronmk
|
def module(value): return type(value).__module__.split('.')
|
| 16 |
|
|
|
| 17 |
|
|
def root_module(value): return module(value)[0]
|
| 18 |
|
|
|
| 19 |
1007
|
aaronmk
|
#### Type checking
|
| 20 |
791
|
aaronmk
|
|
| 21 |
|
|
class ConstraintError(ValueError):
|
| 22 |
|
|
def __init__(self, check_func, value):
|
| 23 |
795
|
aaronmk
|
ValueError.__init__(self, str(value)+' must satisfy constraint '
|
| 24 |
|
|
+check_func.__name__)
|
| 25 |
791
|
aaronmk
|
|
| 26 |
836
|
aaronmk
|
def cast(type_, val):
|
| 27 |
1046
|
aaronmk
|
'''Passes None through. Does not cast a subclass to a superclass (which
|
| 28 |
|
|
doesn't make sense in a dynamically-typed language).'''
|
| 29 |
|
|
if val != None and not isinstance(val, type_): val = type_(val)
|
| 30 |
836
|
aaronmk
|
return val
|
| 31 |
|
|
|
| 32 |
791
|
aaronmk
|
def is_str(val): return isinstance(val, basestring)
|
| 33 |
|
|
|
| 34 |
1007
|
aaronmk
|
def is_list(val): return isinstance(val, list)
|
| 35 |
|
|
|
| 36 |
1046
|
aaronmk
|
#### Basic types
|
| 37 |
|
|
|
| 38 |
|
|
def none_if(val, none_val):
|
| 39 |
|
|
if cast(type(none_val), val) == none_val: return None
|
| 40 |
|
|
else: return val
|
| 41 |
|
|
|
| 42 |
791
|
aaronmk
|
#### Iterables
|
| 43 |
|
|
|
| 44 |
135
|
aaronmk
|
def first(iter_): return iter_.next()
|
| 45 |
|
|
|
| 46 |
133
|
aaronmk
|
def skip(iter_, func):
|
| 47 |
|
|
# Advance iter while func is True
|
| 48 |
|
|
try:
|
| 49 |
|
|
while func(iter_.curr()): iter_.next()
|
| 50 |
|
|
except StopIteration: pass # nothing after the matching elements
|
| 51 |
|
|
|
| 52 |
1147
|
aaronmk
|
class WrapIter:
|
| 53 |
|
|
def __init__(self, wrap_func, iterable):
|
| 54 |
|
|
self.wrap_func = wrap_func
|
| 55 |
|
|
self.iter_ = iterable.__iter__()
|
| 56 |
|
|
|
| 57 |
|
|
def __iter__(self): return self
|
| 58 |
|
|
|
| 59 |
|
|
def next(self): return self.wrap_func(self.iter_.next())
|
| 60 |
934
|
aaronmk
|
|
| 61 |
791
|
aaronmk
|
class CheckedIter:
|
| 62 |
|
|
def __init__(self, check_func, iterable):
|
| 63 |
|
|
self.check_func = check_func
|
| 64 |
|
|
self.iter_ = iterable.__iter__()
|
| 65 |
|
|
|
| 66 |
|
|
def __iter__(self): return self
|
| 67 |
|
|
|
| 68 |
|
|
def next(self):
|
| 69 |
|
|
entry = self.iter_.next()
|
| 70 |
|
|
if self.check_func(entry): return entry
|
| 71 |
|
|
else: raise ConstraintError(self.check_func, entry)
|
| 72 |
|
|
|
| 73 |
1008
|
aaronmk
|
#### Lists
|
| 74 |
|
|
|
| 75 |
|
|
def list_get(list_, idx, default=None):
|
| 76 |
|
|
try: return list_[idx]
|
| 77 |
|
|
except IndexError: return default
|
| 78 |
|
|
|
| 79 |
1147
|
aaronmk
|
def list_subset(list_, idxs):
|
| 80 |
|
|
subset = []
|
| 81 |
|
|
for idx in idxs:
|
| 82 |
|
|
try: subset.append(list_[idx])
|
| 83 |
|
|
except IndexError: pass
|
| 84 |
|
|
return subset
|
| 85 |
|
|
|
| 86 |
1012
|
aaronmk
|
def list_eq_is(list0, list1):
|
| 87 |
|
|
'''Compares two lists using is'''
|
| 88 |
|
|
if len(list0) != len(list1): return False
|
| 89 |
|
|
for i in xrange(len(list0)):
|
| 90 |
|
|
if list0[i] is not list1[i]: return False
|
| 91 |
|
|
return True
|
| 92 |
|
|
|
| 93 |
1145
|
aaronmk
|
def list_flip(list_): return dict((v, i) for i, v in enumerate(list_))
|
| 94 |
|
|
|
| 95 |
791
|
aaronmk
|
#### Dicts
|
| 96 |
|
|
|
| 97 |
330
|
aaronmk
|
def rename_key(dict_, orig, new): dict_[new] = dict_.pop(orig)
|
| 98 |
466
|
aaronmk
|
|
| 99 |
467
|
aaronmk
|
def dict_subset(dict_, keys):
|
| 100 |
|
|
subset = dict()
|
| 101 |
|
|
for key in keys:
|
| 102 |
|
|
try: subset[key] = dict_[key]
|
| 103 |
|
|
except KeyError: pass
|
| 104 |
|
|
return subset
|
| 105 |
1068
|
aaronmk
|
|
| 106 |
|
|
class DefaultDict(collections.defaultdict):
|
| 107 |
|
|
def __init__(self, dict_, default=None):
|
| 108 |
|
|
collections.defaultdict.__init__(self, lambda: default, dict_)
|
| 109 |
|
|
|
| 110 |
|
|
def dict_subset_right_join(dict_, keys):
|
| 111 |
|
|
'''Gets a subset of a dict, using None for subset keys that don't exist'''
|
| 112 |
|
|
return dict_subset(DefaultDict(dict_), keys)
|
| 113 |
1147
|
aaronmk
|
|
| 114 |
|
|
class ListDict:
|
| 115 |
|
|
'''Views a list as a dict, given a key->index mapping'''
|
| 116 |
|
|
def __init__(self, list_, keys, key_idxs=None):
|
| 117 |
|
|
assert len(keys) == len(list_)
|
| 118 |
|
|
if key_idxs == None: key_idxs = list_flip(keys)
|
| 119 |
|
|
self.list = list_
|
| 120 |
|
|
self.keys = keys
|
| 121 |
|
|
self.key_idxs = key_idxs
|
| 122 |
|
|
|
| 123 |
|
|
def __getitem__(self, key): return self.list[self.key_idxs[key]]
|
| 124 |
|
|
|
| 125 |
1178
|
aaronmk
|
def __str__(self): return '{\n'+(''.join(str(k)+': '+str(v)+'\n'
|
| 126 |
|
|
for k, v in zip(self.keys, self.list)))+'}\n'
|
