本文整理汇总了Python中types.MappingProxyType.keys方法的典型用法代码示例。如果您正苦于以下问题：Python MappingProxyType.keys方法的具体用法？Python MappingProxyType.keys怎么用？Python MappingProxyType.keys使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类types.MappingProxyType的用法示例。
在下文中一共展示了MappingProxyType.keys方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: object
# 需要导入模块: from types import MappingProxyType [as 别名]
# 或者: from types.MappingProxyType import keys [as 别名]
class Composition:
"""
Defines a composition of a compound.
To create a composition, use the class methods:
- :meth:`from_pure`
- :meth:`from_formula`
- :meth:`from_mass_fractions`
- :meth:`from_atomic_fractions`
Use the following attributes to access the composition values:
- :attr:`mass_fractions`: :class:`dict` where the keys are atomic numbers and the values weight fractions.
- :attr:`atomic_fractions`: :class:`dict` where the keys are atomic numbers and the values atomic fractions.
- :attr:`formula`: chemical formula
The composition object is immutable, i.e. it cannot be modified once created.
Equality can be checked.
It is hashable.
It can be pickled or copied.
"""
_key = object()
PRECISION = 0.000000001 # 1ppb
def __init__(self, key, mass_fractions, atomic_fractions, formula):
"""
Private constructor. It should never be used.
"""
if key != Composition._key:
raise TypeError('Composition cannot be created using constructor')
if set(mass_fractions.keys()) != set(atomic_fractions.keys()):
raise ValueError('Mass and atomic fractions must have the same elements')
self.mass_fractions = MappingProxyType(mass_fractions)
self.atomic_fractions = MappingProxyType(atomic_fractions)
self._formula = formula
@classmethod
def from_pure(cls, z):
"""
Creates a pure composition.
Args:
z (int): atomic number
"""
return cls(cls._key, {z: 1.0}, {z: 1.0}, pyxray.element_symbol(z))
@classmethod
def from_formula(cls, formula):
"""
Creates a composition from a chemical formula.
Args:
formula (str): chemical formula
"""
atomic_fractions = convert_formula_to_atomic_fractions(formula)
return cls.from_atomic_fractions(atomic_fractions)
@classmethod
def from_mass_fractions(cls, mass_fractions, formula=None):
"""
Creates a composition from a mass fraction :class:`dict`.
Args:
mass_fractions (dict): mass fraction :class:`dict`.
The keys are atomic numbers and the values weight fractions.
Wildcard are accepted, e.g. ``{5: '?', 25: 0.4}`` where boron
will get a mass fraction of 0.6.
formula (str): optional chemical formula for the composition.
If ``None``, a formula will be generated for the composition.
"""
mass_fractions = process_wildcard(mass_fractions)
atomic_fractions = convert_mass_to_atomic_fractions(mass_fractions)
if not formula:
formula = generate_name(atomic_fractions)
return cls(cls._key, mass_fractions, atomic_fractions, formula)
@classmethod
def from_atomic_fractions(cls, atomic_fractions, formula=None):
"""
Creates a composition from an atomic fraction :class:`dict`.
Args:
atomic_fractions (dict): atomic fraction :class:`dict`.
The keys are atomic numbers and the values atomic fractions.
Wildcard are accepted, e.g. ``{5: '?', 25: 0.4}`` where boron
will get a atomic fraction of 0.6.
formula (str): optional chemical formula for the composition.
If ``None``, a formula will be generated for the composition.
"""
atomic_fractions = process_wildcard(atomic_fractions)
mass_fractions = convert_atomic_to_mass_fractions(atomic_fractions)
if not formula:
formula = generate_name(atomic_fractions)
return cls(cls._key, mass_fractions, atomic_fractions, formula)
def __len__(self):
return len(self.mass_fractions)
#.........这里部分代码省略.........