I'd like to use namedtuples internally, but I want to preserve compatibility with users that feed me ordinary tuples.
from collections import namedtuple
tuple_pi = (1, 3.14, "pi") #Normal tuple
Record = namedtuple("Record", ["ID", "Value", "Name"])
named_e = Record(2, 2.79, "e") #Named tuple
named_pi = Record(tuple_pi) #Error
TypeError: __new__() missing 2 required positional arguments: 'Value' and 'Name'
tuple_pi.__class__ = Record
TypeError: __class__ assignment: only for heap types
You can use the *args
call syntax:
named_pi = Record(*tuple_pi)
This passes in each element of the tuple_pi
sequence as a separate argument.
You can also use the namedtuple._make()
class method to turn any sequence into an instance:
named_pi = Record._make(tuple_pi)
Demo:
>>> from collections import namedtuple
>>> Record = namedtuple("Record", ["ID", "Value", "Name"])
>>> tuple_pi = (1, 3.14, "pi")
>>> Record(*tuple_pi)
Record(ID=1, Value=3.14, Name='pi')
>>> Record._make(tuple_pi)
Record(ID=1, Value=3.14, Name='pi')