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Lookup

This page shows how pick finds the one rating that covers a question. It returns a Pick, which holds either the found range or an Issue.

pick

pick takes a tuple of Range and the conditions to ask for. Each condition is a Quantity, a Range or an enum member. The contact table below has three rows.

from elecdef import At, Range, Role, Unit as U, pick
from elecdef.vocab import Current, Utilisation

rows = (
    Range(Role.RATED, nom=U.A(6), at=At(Range(Role.LIMITING, max=U.V(250)), Current.AC, Utilisation.AC_15)),
    Range(Role.RATED, nom=U.A(10), at=At(Range(Role.LIMITING, max=U.V(250)), Current.AC, Utilisation.AC_1)),
    Range(Role.RATED, nom=U.A(6), at=At(Range(Role.LIMITING, max=U.V(24)), Current.DC, Utilisation.DC_13)),
)
assert pick(rows, U.V(24), Current.DC, Utilisation.DC_13).found is rows[2]

Pick

A Pick holds exactly one of found and issue. A found answer has no issue, and a refused answer has no range.

from elecdef import At, Pick, Range, Role, Unit as U, pick
from elecdef.vocab import Current, Utilisation

rows = (
    Range(Role.RATED, nom=U.A(6), at=At(Range(Role.LIMITING, max=U.V(250)), Current.AC, Utilisation.AC_15)),
    Range(Role.RATED, nom=U.A(10), at=At(Range(Role.LIMITING, max=U.V(250)), Current.AC, Utilisation.AC_1)),
    Range(Role.RATED, nom=U.A(6), at=At(Range(Role.LIMITING, max=U.V(24)), Current.DC, Utilisation.DC_13)),
)
answer = pick(rows, U.V(24), Current.DC, Utilisation.DC_13)
assert isinstance(answer, Pick)
assert answer.issue is None

Issue and IssueCode

When no row covers the ask, pick returns an Issue with the code NO_RATING. When two rows cover it, the code is AMBIGUOUS_RATING.

from elecdef import At, Issue, IssueCode, Range, Role, Unit as U, pick
from elecdef.vocab import Current, Utilisation

rows = (
    Range(Role.RATED, nom=U.A(6), at=At(Range(Role.LIMITING, max=U.V(250)), Current.AC, Utilisation.AC_15)),
    Range(Role.RATED, nom=U.A(10), at=At(Range(Role.LIMITING, max=U.V(250)), Current.AC, Utilisation.AC_1)),
    Range(Role.RATED, nom=U.A(6), at=At(Range(Role.LIMITING, max=U.V(24)), Current.DC, Utilisation.DC_13)),
)
no_rating = pick(rows, U.V(400), Current.AC, Utilisation.AC_15)
assert no_rating.found is None
assert isinstance(no_rating.issue, Issue)
assert no_rating.issue.code is IssueCode.NO_RATING
assert pick(rows, Current.AC).issue.code is IssueCode.AMBIGUOUS_RATING