Simple append list to class variable in python

Question

I have this simple class in Python. Name is a string, events are list of strings.

class Page(object):

    def __init__(self, name=None, events=None):
        self.name = name
        self.events = events or []

    def add(self, x):
        return self.events.append(x)

    @property
    def eventstring(self):
        return " , ".join(self.events)

I have this input:

 log = {'key1': [['e1', 'e2'], 'e3', ]], 'key2': ['e5', 'e6', 'e7']}

I want to create read in the log and produce list of pages. i.e.

[Page('key1', ['e1', 'e2', 'e3']), Page('key2', ['e5', 'e6', 'e7']}

My current code to create the list of Page objects doesn't work. Plus, getting AttributeError: 'NoneType' object has no attribute 'append' error msg.

def inputevent(inputlog):
    final_pages = []
    pg = Page()
    for key, val in inputlog.items():
        pg.name = key
        for e in val:
            pg.events = pg.add(e)
        final_pages.append(pg)
    final_pages.append(pg)
return final_pages

What is the full traceback of the exception?

Martijn Pieters
– Martijn Pieters

2014-03-11 22:15:58 +00:00
Commented Mar 11, 2014 at 22:15 — Martijn Pieters
– Martijn Pieters, Commented Mar 11, 2014 at 22:15

Martijn Pieters · Accepted Answer · 2014-03-11 22:17:14Z

2

Page.add() returns None, but you are assigning it back to pg.events:

pg.events = pg.add(e)

This effectively clears pg.events. Since pg.add() alters pg.events in-place, there is no need to assign back to pg.events there at all:

for key, val in inputlog.items():
    pg.name = key
    for e in val:
        pg.add(e)

answered Mar 11, 2014 at 22:17

Martijn Pieters

1.1m326 gold badges4.2k silver badges3.4k bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Simple append list to class variable in python

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related