Class method which creates bag from iterable adding optional count for each item. >>> b = Bag({'b': 2, 'c': 1, 'a': 3}) >>> b2 = Bag.fromkeys(['a', 'b', 'c', 'b', 'a', 'a']) >>> b3 = Bag.fromkeys("abacab") >>> assert b == b2 == b3 >>> word_count = Bag.fromke
(cls, iterable, count=1)
| 39 | self[key] += count |
| 40 | |
| 41 | def fromkeys(cls, iterable, count=1): |
| 42 | """Class method which creates bag from iterable adding optional count for each item. |
| 43 | |
| 44 | >>> b = Bag({'b': 2, 'c': 1, 'a': 3}) |
| 45 | >>> b2 = Bag.fromkeys(['a', 'b', 'c', 'b', 'a', 'a']) |
| 46 | >>> b3 = Bag.fromkeys("abacab") |
| 47 | >>> assert b == b2 == b3 |
| 48 | |
| 49 | >>> word_count = Bag.fromkeys("how much wood could a wood chuck chuck".split()) |
| 50 | >>> print(word_count) |
| 51 | {'a': 1, 'chuck': 2, 'could': 1, 'how': 1, 'much': 1, 'wood': 2} |
| 52 | |
| 53 | An optional count can be specified. Count added each time item is encountered. |
| 54 | >>> print(Bag.fromkeys("abacab", 5)) |
| 55 | {'a': 15, 'b': 10, 'c': 5} |
| 56 | """ |
| 57 | b = cls() |
| 58 | for key in iterable: #could just return b.__iadd__(iterable, count) |
| 59 | b[key] += count #perhaps slower than necessary but will simplify derived classes that override __setitem__() |
| 60 | return b |
| 61 | |
| 62 | fromkeys = classmethod(fromkeys) |
| 63 |