Adding the ability to control length to __format__ by WeiGodHorse · Pull Request #54 · fluentpython/example-code

Expand Up @@ -187,6 +187,65 @@ '<4.000e+00, 1.047e+00, 9.553e-01, 7.854e-01>' >>> format(Vector([0, 1, 0, 0]), '0.5fh') '<1.00000, 1.57080, 0.00000, 0.00000>'
Tests of new ``format()`` with length limit::
>>> v5 = Vector(range(5)) >>> v100 = Vector(range(100)) >>> format(v5) '(0.0, 1.0, 2.0, 3.0, 4.0)' >>> format(v5, 'h') # doctest:+ELLIPSIS '<5.477..., 1.5707..., 1.387..., 1.190..., 0.927...>' >>> format(v5, '0.3fh') '<5.477, 1.571, 1.387, 1.190, 0.927>' >>> format(v5, '*') '(0.0, 1.0, 2.0, 3.0, 4.0)' >>> format(v5, '.3f*') '(0.000, 1.000, 2.000, 3.000, 4.000)' >>> format(v5, '.3fh*') '<5.477, 1.571, 1.387, 1.190, 0.927>'
>>> v30 = Vector(range(30)) >>> format(v30) # doctest:+ELLIPSIS '(0.0, 1.0, ..., 29.0)' >>> format(v30, 'h') # doctest:+ELLIPSIS '<92.493..., 1.570..., ..., 0.802...>' >>> format(v30, '0.3fh') # doctest:+ELLIPSIS '<92.493, 1.571, ..., 0.803>' >>> format(v30, '*') # doctest:+ELLIPSIS '(0.0, 1.0, ..., 29.0)' >>> format(v30, '.3f*') # doctest:+ELLIPSIS '(0.000, 1.000, ..., 29.000)' >>> format(v30, '.3fh*') # doctest:+ELLIPSIS '<92.493, 1.571, ..., 0.803>'
>>> v100 = Vector(range(100)) >>> format(v100) # doctest:+ELLIPSIS '(0.0, 1.0, ..., 29.0, ...)' >>> format(v100, 'h') # doctest:+ELLIPSIS '<573.018..., 1.570..., ..., 1.521..., ...>' >>> format(v100, '0.3fh') # doctest:+ELLIPSIS '<573.018, 1.571, ..., 1.521, ...>' >>> format(v100, '*') # doctest:+ELLIPSIS '(0.0, 1.0, ..., 99.0)' >>> format(v100, '.3f*') # doctest:+ELLIPSIS '(0.000, 1.000, ..., 99.000)' >>> format(v100, '.3fh*') # doctest:+ELLIPSIS '<573.018, 1.571, ..., 0.790>'
>>> v100.maxlen = 3 >>> format(v100) '(0.0, 1.0, 2.0, ...)' >>> format(v100, 'h') # doctest:+ELLIPSIS '<573.018..., 1.570..., 1.569..., ...>' >>> format(v100, '0.3fh') '<573.018, 1.571, 1.569, ...>' >>> format(v100, '*') # doctest:+ELLIPSIS '(0.0, 1.0, ..., 99.0)' >>> format(v100, '.3f*') # doctest:+ELLIPSIS '(0.000, 1.000, ..., 99.000)' >>> format(v100, '.3fh*') # doctest:+ELLIPSIS '<573.018, 1.571, ..., 0.790>' """
from array import array Expand Down Expand Up @@ -228,10 +287,10 @@ def __hash__(self): return functools.reduce(operator.xor, hashes, 0)
def __abs__(self): return math.sqrt(sum(x * x for x in self)) return math.hypot(*self)
def __bool__(self): return bool(abs(self)) return any(x != 0 for x in self)
def __len__(self): return len(self._components) Expand Down Expand Up @@ -268,16 +327,30 @@ def angle(self, n): # <2> def angles(self): # <3> return (self.angle(n) for n in range(1, len(self)))
maxlen = 30 def __format__(self, fmt_spec=''): print_all = len(self) <= self.maxlen # whether print all numbers if fmt_spec.endswith('*'): fmt_spec = fmt_spec[:-1] print_all = True if fmt_spec.endswith('h'): # hyperspherical coordinates fmt_spec = fmt_spec[:-1] coords = itertools.chain([abs(self)], self.angles()) # <4> if print_all: coords = itertools.chain([abs(self)], self.angles()) # <4> else: coords = itertools.chain([abs(self)], itertools.islice(self.angles(), self.maxlen -1)) outer_fmt = '<{}>' # <5> else: coords = self if print_all: coords = self else: coords = itertools.islice(self, self.maxlen) outer_fmt = '({})' # <6> components = (format(c, fmt_spec) for c in coords) # <7> if not print_all: components = itertools.chain(components, ['...']) return outer_fmt.format(', '.join(components)) # <8>
@classmethod Expand Down