Python: calling class to print Tweet contents

Question

I'm trying to filter tweets by hashtag and output the text of the Tweet.

The class Tweet contains the overarching tweet info, of which I only need "text". I know that str method needs to be used to call each instance of the class, but down below when I "print", the above class is inaccessible. Please help :D

Edit: what's the implication of replacing __str__ with __repr__ in class Tweet? Thanks!

class Tweet():

    tweet = Tweet()
    def __init__(self, tweet_dict = {}):        
        if "statuses" in tweet_dict:
            self.status = tweet_dict["statuses"]
        else:
            self.status = ""

        if "text" in self.status:
            self.text = item["text"]
        else:
            self.text = ""

    def __str__(self):
        tweet_info = self.text
        return tweet_info

#-------------------------------------------------------------------

tweet_inst = []
for dic in statuses:
    item_instances = Tweet(dic)
    tweet_inst.append(item_instances)
print(tweet_inst)

Could you please fix the code block formatting? The `tweet = Tweet()` line looks fishy, but I can't tell if it is actually part of the class body. If it is, this will be one of your problems I guess. — shmee, Apr 10 '18 at 06:06

Chen A. · Answer 1 · 2018-04-10T07:26:49.273

__str__ needs to return a string representation of the object.

__str__ goal is to be readable, __repr__ goal is to be unambiguous.

When you print a list (which is tweet_inst), it iterates over the objects (of Tweet) contained in the list and call their __repr__.

You want to add def __repr__(self): return str(self) so they do the same thing, then it will return self.text instead of the object default representation (which is it's location in memory)

class Tweet(object):

    def __init__(self, x):
        self.x = x

    def __str__(self):
        return self.x

    def __repr__(self):
        return '__repr__' + str(self.x)

>>> t1 = Tweet('t1')
>>> t2 = Tweet('t2')
>>> list_ = [t1, t2]
>>> print(list_)
[__repr__t1, __repr__t2]

Rather than the default
[<__main__.Tweet object at 0x02AFA810>, <__main__.Tweet object at 0x029E2BF0>]

Here is a great answer by moshez about the difference between the two.

Actually, I think the OP does return tweet_info in `__str__`, just the formatting of the code block is broken, which is why I asked to fix it. — shmee, Apr 10 '18 at 07:06
@shmee You're right, it was out of the code block, written in bold so I didn't notice. — Chen A., Apr 10 '18 at 07:24

score 0 · Answer 2 · answered Apr 10 '18 at 07:26

First of all, the second line, tweet = Tweet() in the class definition is wrong. You cannot create a class variable containing an instance of said class.

Second, you assign self.text = item["text"] in line 11. What is item? Should that rather be tweet_dict?

Third, you could directly return self.text in __str__, no need to assign it to a varibale tweet_info first.

Last, but not least, you should not use mutable datatypes as default arguments, like you do in line 4. Here's why.

Python: calling class to print Tweet contents

2 Answers2