What's wrong with my Python code? An example in Head First Python

Question

It says

    sarah = Athlete('Sarah Sweeney', '2002-6-17', ['2:58', '2.58', '1.56'])
TypeError: object() takes no parameters

What's wrong? Thank you. It is the example in Head First Python

class Athlete:
    def _init_(self, a_name, a_dob=None, a_times=[]):
        self.name = a_name
        self.dob = a_dob
        self.times = a_times

sarah = Athlete('Sarah Sweeney', '2002-6-17', ['2:58', '2.58', '1.56'])

You *probably* do **not** want to use a mutable list value `[]` for a default, see ["Least Astonishment" in Python: The Mutable Default Argument](http://stackoverflow.com/q/1132941) — Martijn Pieters, Nov 11 '13 at 15:50
I hope you've read: http://stackoverflow.com/questions/1132941/least-astonishment-in-python-the-mutable-default-argument — Bakuriu, Nov 11 '13 at 15:51

score 4 · Accepted Answer · edited May 23 '17 at 12:12

That's because you don't overload magic __init__ method of the object class. Instead of that you define a new method called _init_ which has no special meaning to Python (special methods in Python should be surrounded with double underscores).

As far as your class does not overload __init__, a default one (inherited from object) gets called every time you instantiate the class. And that default one takes no arguments.

See also: Special (magic) methods in Python, Where is the Python documentation for the special methods? (__init__, __new__, __len__, ...)

score 3 · Answer 2 · answered Nov 11 '13 at 15:50

3

You've misspelt __init__ (note the double underscores at the start and the end).

answered Nov 11 '13 at 15:50

NPE

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What's wrong with my Python code? An example in Head First Python

2 Answers2