Python3 inheritance from collections.namedtuple: TypeError: object.__init__() takes exactly one argument (the instance to initialize)
Question:
I want to create a child class of collections.namedtuple
This is my code:
from collections import namedtuple
TransactionTuple = namedtuple(
typename="Transactionttt",
field_names=[
"transactionDate",
"valueDate",
"value",
"currency",
"concept"
],
defaults=("",)
)
class TransactionClass(TransactionTuple):
def __init__(self, transactionDate, valueDate, value, currency, concept):
super().__init__(transactionDate, valueDate, value, currency, concept)
print(TransactionClass(1,1,1,1,1))
And this is the output:
Traceback (most recent call last):
File "D:Sync1CodePython3EconoPyVersion_0.2test.py", line 22, in <module>
print(TransactionClass(1,1,1,1,1))
File "D:Sync1CodePython3EconoPyVersion_0.2test.py", line 20, in __init__
super().__init__(transactionDate, valueDate, value, currency, concept)
TypeError: object.__init__() takes exactly one argument (the instance to initialize)
I think that the problem is related to super().__init__(), but I don’t find a solution.
Answers:
from collections import namedtuple
TransactionTuple = namedtuple(
typename="Transactionttt",
field_names=[
"transactionDate",
"valueDate",
"value",
"currency",
"concept"
],
defaults=("",)
)
class TransactionClass(TransactionTuple):
def __init__(self, transactionDate, valueDate, value, currency, concept):
super().__init__()
print(TransactionTuple(1, 1, 1, 1, 1))
print(TransactionClass(1, 1, 1, 1, 1))
produces
Transactionttt(transactionDate=1, valueDate=1, value=1, currency=1, concept=1)
TransactionClass(transactionDate=1, valueDate=1, value=1, currency=1, concept=1)
My guess is that the class from namedtuple populates its instance through the __new__ function, and so doesn’t actually take anything into its __init__() (just a guess). So if you have other things, you should be able to add them to the __init__() you have, or if that’s it, then you can just remove it.
I want to create a child class of collections.namedtuple
This is my code:
from collections import namedtuple
TransactionTuple = namedtuple(
typename="Transactionttt",
field_names=[
"transactionDate",
"valueDate",
"value",
"currency",
"concept"
],
defaults=("",)
)
class TransactionClass(TransactionTuple):
def __init__(self, transactionDate, valueDate, value, currency, concept):
super().__init__(transactionDate, valueDate, value, currency, concept)
print(TransactionClass(1,1,1,1,1))
And this is the output:
Traceback (most recent call last):
File "D:Sync1CodePython3EconoPyVersion_0.2test.py", line 22, in <module>
print(TransactionClass(1,1,1,1,1))
File "D:Sync1CodePython3EconoPyVersion_0.2test.py", line 20, in __init__
super().__init__(transactionDate, valueDate, value, currency, concept)
TypeError: object.__init__() takes exactly one argument (the instance to initialize)
I think that the problem is related to super().__init__(), but I don’t find a solution.
from collections import namedtuple
TransactionTuple = namedtuple(
typename="Transactionttt",
field_names=[
"transactionDate",
"valueDate",
"value",
"currency",
"concept"
],
defaults=("",)
)
class TransactionClass(TransactionTuple):
def __init__(self, transactionDate, valueDate, value, currency, concept):
super().__init__()
print(TransactionTuple(1, 1, 1, 1, 1))
print(TransactionClass(1, 1, 1, 1, 1))
produces
Transactionttt(transactionDate=1, valueDate=1, value=1, currency=1, concept=1)
TransactionClass(transactionDate=1, valueDate=1, value=1, currency=1, concept=1)
My guess is that the class from namedtuple populates its instance through the __new__ function, and so doesn’t actually take anything into its __init__() (just a guess). So if you have other things, you should be able to add them to the __init__() you have, or if that’s it, then you can just remove it.