algebraixlib.undef module¶
Class Undef (represents the concept of ‘undefined’) and associated constructs.
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class
algebraixlib.undef.
Undef
[source]¶ Bases:
object
A singleton class that represents the concept of “undefined”. It can’t be treated as a value by the Data Algebra library and specifically it will never appear as the value of an Atom.
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__hash__
= None¶
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class
algebraixlib.undef.
RaiseOnUndef
[source]¶ Bases:
object
Manage the level for make_or_raise_undef(). Implemented as static class.
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static
get_level
()[source]¶ Return the current level for raising an UndefException.
The exception is raised if the ‘level’ argument of make_or_raise_undef() is less than or equal to the value returned here.
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static
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exception
algebraixlib.undef.
UndefException
[source]¶ Bases:
Exception
This exception is raised when the ‘level’ argument of make_or_raise_undef() is less than or equal to the RaiseOnUndef level.
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algebraixlib.undef.
make_or_raise_undef
(level=1)[source]¶ Raise UndefException if level is less than or equal to the RaiseOnUndef level, otherwise return Undef().
Parameters: level – An integer >= 1. Default is 1. Note
Use 1 (or no argument) for the cases that are most likely to be errors (like wrong argument types). Use higher numbers for cases that may return Undef() on purpose.