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def | __init__ (self, doc, dtype, allowed, default=None, optional=True) |
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def | rename (self, instance) |
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def | validate (self, instance) |
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def | freeze (self, instance) |
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def | save (self, outfile, instance) |
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def | toDict (self, instance) |
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def | __get__ (self, instance, owner=None, at=None, label="default") |
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def | __set__ (self, instance, value, at=None, label='assignment') |
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def | __delete__ (self, instance, at=None, label='deletion') |
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A configuration field (`~lsst.pex.config.Field` subclass) that allows a
user to select from a predefined set of values.
Use ``ChoiceField`` when a configuration can only take one of a predefined
set of values. Each choice must be of the same type.
Parameters
----------
doc : `str`
Documentation string that describes the configuration field.
dtype : class
The type of the field's choices. For example, `str` or `int`.
allowed : `dict`
The allowed values. Keys are the allowed choices (of ``dtype``-type).
Values are descriptions (`str`-type) of each choice.
default : ``dtype``-type, optional
The default value, which is of type ``dtype`` and one of the allowed
choices.
optional : `bool`, optional
If `True`, this configuration field is *optional*. Default is `True`.
See also
--------
ConfigChoiceField
ConfigDictField
ConfigField
ConfigurableField
DictField
Field
ListField
RangeField
RegistryField
Definition at line 28 of file choiceField.py.
def lsst.pex.config.config.Field.__set__ |
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self, |
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instance, |
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value, |
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at = None , |
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label = 'assignment' |
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) |
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inherited |
Set an attribute on the config instance.
Parameters
----------
instance : `lsst.pex.config.Config`
The config instance that contains this field.
value : obj
Value to set on this field.
at : `list` of `lsst.pex.config.callStack.StackFrame`
The call stack (created by
`lsst.pex.config.callStack.getCallStack`).
label : `str`, optional
Event label for the history.
Notes
-----
This method is invoked by the owning `lsst.pex.config.Config` object
and should not be called directly.
Derived `~lsst.pex.config.Field` classes may need to override the
behavior. When overriding ``__set__``, `~lsst.pex.config.Field` authors
should follow the following rules:
- Do not allow modification of frozen configs.
- Validate the new value **before** modifying the field. Except if the
new value is `None`. `None` is special and no attempt should be made
to validate it until `lsst.pex.config.Config.validate` is called.
- Do not modify the `~lsst.pex.config.Config` instance to contain
invalid values.
- If the field is modified, update the history of the
`lsst.pex.config.field.Field` to reflect the changes.
In order to decrease the need to implement this method in derived
`~lsst.pex.config.Field` types, value validation is performed in the
`lsst.pex.config.Field._validateValue`. If only the validation step
differs in the derived `~lsst.pex.config.Field`, it is simpler to
implement `lsst.pex.config.Field._validateValue` than to reimplement
``__set__``. More complicated behavior, however, may require
reimplementation.
Definition at line 506 of file config.py.
def lsst.pex.config.config.Field.toDict |
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self, |
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instance |
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inherited |
Convert the field value so that it can be set as the value of an
item in a `dict` (for internal use only).
Parameters
----------
instance : `Config`
The `Config` that contains this field.
Returns
-------
value : object
The field's value. See *Notes*.
Notes
-----
This method invoked by the owning `~lsst.pex.config.Config` object and
should not be called directly.
Simple values are passed through. Complex data structures must be
manipulated. For example, a `~lsst.pex.config.Field` holding a
subconfig should, instead of the subconfig object, return a `dict`
where the keys are the field names in the subconfig, and the values are
the field values in the subconfig.
Definition at line 461 of file config.py.