Yes it does, it works exactly as documented. ._replace returns a new namedtuple, it does not modify the original, so you need to write this: p = p._replace(x=33) See here: somenamedtuple._replace(kwargs) for more information.
Python and its community are wrestling with the “struct” problem: how to best group related values into composite data objects that allow logical/easy accessing of components (typically by name). There are many competing approaches: collections.namedtuple instances dictionaries (with a fixed/known set of keys) attribute-accessible dictionaries (like stuf) the attrs library PEP 557 dataclasses plain old … Read more
If you’re trying to get the actual names, use the _fields attribute: from collections import namedtuple Point = namedtuple(‘Point’, ‘x, y’) p = Point(x=1, y=2) for name in Point._fields: print(name, getattr(p, name))
Python <3.3 You mean something like this? class Record(object): __slots__= “attribute1”, “attribute2”, “attribute3”, def items(self): “dict style items” return [ (field_name, getattr(self, field_name)) for field_name in self.__slots__] def __iter__(self): “iterate over fields tuple/list style” for field_name in self.__slots__: yield getattr(self, field_name) def __getitem__(self, index): “tuple/list style getitem” return getattr(self, self.__slots__[index]) >>> r= Record() >>> r.attribute1= … Read more
I suggest you use the the _replace method from collections import namedtuple C = namedtuple(‘C’, ‘x, y’) c = C(x=10, y=20) # c.x = 30 won’t work c = c._replace(x=30)
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”]) >>> … Read more
Calling the function collections.namedtuple gives you a new type that’s a subclass of tuple (and no other classes) with a member named _fields that’s a tuple whose items are all strings. So you could check for each and every one of these things: def isnamedtupleinstance(x): t = type(x) b = t.__bases__ if len(b) != 1 … Read more
In a function call *t means “treat the elements of this iterable as positional arguments to this function call.” def foo(x, y): print(x, y) >>> t = (1, 2) >>> foo(*t) 1 2 Since v3.5, you can also do this in a list/tuple/set literals: >>> [1, *(2, 3), 4] [1, 2, 3, 4] **d means … Read more
Create the named tuple outside of the function: from collections import namedtuple import pickle P = namedtuple(“P”, “one two three four”) def pickle_test(): my_list = [] abe = P(“abraham”, “lincoln”, “vampire”, “hunter”) my_list.append(abe) with open(‘abe.pickle’, ‘wb’) as f: pickle.dump(abe, f) pickle_test() Now pickle can find it; it is a module global now. When unpickling, all … Read more
from operator import attrgetter from collections import namedtuple Person = namedtuple(‘Person’, ‘name age score’) seq = [Person(name=”nick”, age=23, score=100), Person(name=”bob”, age=25, score=200)] Sort list by name sorted(seq, key=attrgetter(‘name’)) Sort list by age sorted(seq, key=attrgetter(‘age’))