CODEWITHSUNDEEP
pythonnamedtuple
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Reputation: 11

How to fix "__new__() missing 3 required positional arguments:.." error in Python

I'm working on a python code and I get this error: "TypeError: new() missing 3 required positional arguments: 'name', 'freq', and 'gen'"

I'm importing a csv file to create a list of tuples, using a namedtuple.

import csv
from collections import namedtuple

Rec = namedtuple('Rec', 'year, name, freq, gen')

def read_file(file):  
    with open(file) as f:
        reader = csv.reader(f)
        next(reader)
        for line in reader:
            recs= Rec(line)
        return recs

read_file("./data/file.csv")

It's probably some newbie problem, but that's what I am :) I'd appreciate any help!

Upvotes: 0

Views: 1663

Answers (1)

NPE
NPE

Reputation: 500853

line is a tuple. When you call Rec(line), that entire tuple gets interpreted as the year argument (with the other three arguments being missing, hence the error).

To fix this, change

recs = Rec(line)

to 

recs = Rec(*line)

or

recs = Rec._make(line)

https://docs.python.org/2/library/collections.html#collections.somenamedtuple._make

Upvotes: 2

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