Python Forum

Here is what the PyBite #181 exercise is calling for:

Quote: Complete the add method of the OrderedList class which takes a num argument and adds that to the self._numbers list keeping it ordered upon insert.
Using a manual .sort() or .sorted() each time is not allowed. Look into the bisect module how to do it ...

I solved the problem (see script below). To come up with my script, I leveraged Python.org’s bisect doc.

The solution I wrote passes all the unit tests but as a ‘victory lap’ I’m exploring how to call classes in general within my script using my trusty REPL and I am doing something wrong because my output doesn’t process as expected.

Here is the script I am working with:

import bisect
 
 
class OrderedList:
 
   def __init__(self):
       self._numbers = []
 
   def add(self, num):
       bisect.insort_right(self._numbers, num)
 
   def __str__(self):
       return ', '.join(str(num) for num in self._numbers)

In my script’s directory, I activate my REPL, import the script and instantiate:

 $ bpython
bpython version 0.19 on top of Python 3.8.5 /usr/bin/python
>>> import order
>>> dummy = order.OrderedList
>>> 

Here are some inputs with my expected outputs:

dummy.add(10)
print(dummy)  
10
dummy.add(1)
print(dummy)
1, 10
dummy.add(16)
print(dummy)
1, 10, 16
dummy.add(5)
print(dummy)
1, 5, 10, 16

But here is my actual output:

 >>> dummy.add(10)
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    dummy.add(10) 

The AttributeError says that the module (order.py) does not contain an attribute (a variable within a class) but as you can see in my script, an attribute is clearly declared at line 7. I believe the problem is not with my script, but with how I am instantiating it in my REPL.

How do I achieve the expected output in my REPL? How do I instantiate and properly pass in integers on the fly in my REPL?

I realize in the PyBite example REPL commands use:

order = OrderedList()
order.add(10)

That seems to work. But when I replace 'order' with 'dummy' (because I am experimenting with an alternate variable name) the output falls apart.

you need to create an instance of OrderedList:

>>> dummy = order.OrderedList()

(Sep-24-2020, 01:35 PM)mlieqo Wrote: [ -> ]you need to create an instance of OrderedList:

>>> dummy = order.OrderedList()

@milego, what you have suggested is fairly similar to what I tried myself. To quote my original post:

>>> import order
>>> dummy = order.OrderedList
>>> 

My problem is that I'm missing the parentheses after OrderedList. I guess when it comes to programming, attention to detail is essential. I will be more careful next time and ensure that I check to include parentheses.

Thanks mlieqo for your answer.