iterating over a set of class instances

Question

let's say we have the following class Boy:

class Boy():

def __init__(self, name, hair, friend=None):
    self.name = name
    self.hair = hair
    self.friend = friend

and we have some instances of this class and we want to iterate it, and change attributes on these instances while iterating. for example:

ben = Boy("Ben", "red")
sam = Boy("Sam", "black")
roger = Boy("Roger", "yellow", sam)
boys = {ben, sam}
for boy in boys:
    boy = roger.friend

The above method only change the attribute of the pointer "boy" and not the instance in the set. What's the best way to approcah this?

Does this answer your question? [Iterating over object instances of a given class in Python](https://stackoverflow.com/questions/739882/iterating-over-object-instances-of-a-given-class-in-python) — Rajat Mishra, Dec 27 '20 at 22:47
you want `boy.friend = roger`, I think (although your precise intention isn't so clear) — Robin Zigmond, Dec 27 '20 at 22:52
@RajatMishra the link you posted doesn't have anything to do with my question. I want to iterate over a *set* and change the instances inside it, not to iterate over an instance attributes. — Golden, Dec 28 '20 at 08:23

TropicsCold · Answer 1 · 2020-12-28T09:07:01.123

-1

For changing attribute of element in the set

Your code below assign the `ref of roger's friend to the ref of boy Actually this did nothing.

for boy in boys:
    boy = roger.friend

Here is the method to change attribute of element in a set iteratively

for boy in boys:
    boy.hair = 'green'
    boy.friend = roger

# Check results
for boy in boys:
    print('----')
    print(boy.name)
    print(boy.hair)
    print(boy.friend.name)

edited Dec 28 '20 at 09:07

answered Dec 28 '20 at 05:44

TropicsCold

115
6

That's not what i meant at all. I want to change the attributes of the instances inside the set.. – Golden Dec 28 '20 at 08:20

iterating over a set of class instances

1 Answers1