diff options
Diffstat (limited to 'Lib/collections.py')
| -rw-r--r-- | Lib/collections.py | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/Lib/collections.py b/Lib/collections.py index 504ae19549..884c91f1e7 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -65,9 +65,9 @@ def namedtuple(typename, field_names, verbose=False): def __new__(cls, %(argtxt)s): return tuple.__new__(cls, (%(argtxt)s)) \n @classmethod - def _make(cls, iterable): + def _make(cls, iterable, new=tuple.__new__, len=len): 'Make a new %(typename)s object from a sequence or iterable' - result = tuple.__new__(cls, iterable) + result = new(cls, iterable) if len(result) != %(numfields)d: raise TypeError('Expected %(numfields)d arguments, got %%d' %% len(result)) return result \n @@ -115,8 +115,22 @@ if __name__ == '__main__': assert p == loads(dumps(p)) # test and demonstrate ability to override methods - Point.__repr__ = lambda self: 'Point(%.3f, %.3f)' % self - print(p) + class Point(namedtuple('Point', 'x y')): + @property + def hypot(self): + return (self.x ** 2 + self.y ** 2) ** 0.5 + def __repr__(self): + return 'Point(x=%.3f, y=%.3f, hypot=%.3f)' % (self.x, self.y, self.hypot) + + print(Point(3, 4),'\n', Point(2, 5), '\n', Point(9./7, 6)) + + class Point(namedtuple('Point', 'x y')): + 'Point class with optimized _make() and _replace() without error-checking' + _make = classmethod(tuple.__new__) + def _replace(self, _map=map, **kwds): + return self._make(_map(kwds.pop, ('x', 'y'), self)) + + print(Point(11, 22)._replace(x=100)) import doctest TestResults = namedtuple('TestResults', 'failed attempted') |