I would appreciate if someone can explain this step by step.

Question

This code will print 1234. I tried to understand how the argument is passed around, but it is not clear. I kinda understand, which also means I kinda don't understand.

######################

class phone:
def __init__(self, number):
self.number = number
number = 1111

ppl = phone(1234)
print(ppl.number)

Answer 1

The object ppl belongs to the phone class thus its constructor accepts a parameter "number".
You pass the value 1234 which becomes a property of the object with self.number=number and you modify "number" AFTERWARDS thus its initial value does not change to 1111...

Answer 2

What's probably confusing you is the 'self' special argument...

If the Python Sololearn course fail to help you, maybe try this link:
https://pythontips.com/2013/08/07/the-self-variable-in-python-explained/

Answer 3

Upon recent reading (I'm also learning Python) I found that in order to achieve the effect similar to "pass by reference" the argument passed into the method/function parameter needs to be an immutable type, apparently, in Python int and string are immutables, hence the change in your method for <number> parameter is not reflected on the method caller space.

Source:
https://stackoverflow.com/questions/986006/how-do-i-pass-a-variable-by-reference

(Answer from a member by the name Raymond Hettinger seems clear enough)

Answer 4

This should help:

https://code.sololearn.com/cjgeT97o58IT/?ref=app