将对象列表写入 csv 文件

Question

我正在编写一个 python 程序，循环遍历 reddit 提交、提取数据并将其作为对象存储在列表中。但是，我无法将该列表写入 csv 文件。该文件已创建，但它只是为对象提供了某种 id 标签。我应该如何更改 csv 代码？

代码

import praw
from datetime import datetime
import pandas as pd

class Submission:
    def __init__(self, time, score, title, text, ofReddit, serious):
        self.time = time
        self.score = score
        self.title = title
        self.text = text
        self.ofReddit = ofReddit
        self.serious = serious
data = []

reddit = praw.Reddit(client_id=id, client_secret=secret,
                     user_agent='testscript by /u/SilentButtDeadlies')
subreddit = reddit.subreddit('AskReddit')
for submission in subreddit.new(limit=50):
    time = datetime.utcfromtimestamp(submission.created_utc).hour
    score = submission.score
    title = len(submission.title)
    text = len(submission.selftext)
    if 'of reddit' in submission.title.lower():
        ofReddit = 1
    else:
        ofReddit = 0
    if '[serious]' in submission.title.lower():
        serious = 1
    else:
        serious = 0
    data.append(Submission(time, score, title, text, ofReddit, serious))
df = pd.DataFrame(data)
filename = 'AskRedditData' + str(datetime.now()) + '.csv'
df.to_csv(filename, index=False, encoding='utf-8')

CSV 文件

0
<__main__.Submission instance at 0x1118f6ef0>
<__main__.Submission instance at 0x1118f68c0>
<__main__.Submission instance at 0x1118f6950>
<__main__.Submission instance at 0x1118c3758>
<__main__.Submission instance at 0x11239c638>
<__main__.Submission instance at 0x11239c5f0>
<__main__.Submission instance at 0x112398908>
<__main__.Submission instance at 0x112398998>
<__main__.Submission instance at 0x112398878>
<__main__.Submission instance at 0x1123989e0>
<__main__.Submission instance at 0x112398c68>
<__main__.Submission instance at 0x11239fe18>
<__main__.Submission instance at 0x11239fe60>
<__main__.Submission instance at 0x11239fea8>
<__main__.Submission instance at 0x11239fef0>
<__main__.Submission instance at 0x11239ff38>
<__main__.Submission instance at 0x11239ff80>
<__main__.Submission instance at 0x11239ffc8>
<__main__.Submission instance at 0x112404050>
<__main__.Submission instance at 0x112404098>
<__main__.Submission instance at 0x1124040e0>
<__main__.Submission instance at 0x112404128>
<__main__.Submission instance at 0x112404170>
<__main__.Submission instance at 0x1124041b8>
<__main__.Submission instance at 0x112404200>
<__main__.Submission instance at 0x112404248>
<__main__.Submission instance at 0x112404290>
<__main__.Submission instance at 0x1124042d8>
<__main__.Submission instance at 0x112404320>
<__main__.Submission instance at 0x112404368>
<__main__.Submission instance at 0x1124043b0>
<__main__.Submission instance at 0x1124043f8>
<__main__.Submission instance at 0x112404440>
<__main__.Submission instance at 0x112404488>
<__main__.Submission instance at 0x1124044d0>
<__main__.Submission instance at 0x112404518>
<__main__.Submission instance at 0x112404560>
<__main__.Submission instance at 0x1124045a8>
<__main__.Submission instance at 0x1124045f0>
<__main__.Submission instance at 0x112404638>
<__main__.Submission instance at 0x112404680>
<__main__.Submission instance at 0x1124046c8>
<__main__.Submission instance at 0x112404710>
<__main__.Submission instance at 0x112404758>
<__main__.Submission instance at 0x1124047a0>
<__main__.Submission instance at 0x1124047e8>
<__main__.Submission instance at 0x112404830>
<__main__.Submission instance at 0x112404878>
<__main__.Submission instance at 0x1124048c0>
<__main__.Submission instance at 0x112404908>

Answer 1

您的提交 class 似乎只是作为一种记录类型。您可能只使用 namedtuple。因此，将您的 class 定义替换为：

from collections import namedtuple
Submission = namedtuple('Submission', ['time', 'score', 'title', 'text', 'ofReddit', 'serious'])

现在您的其余代码应该可以正常工作了。 pandas 不知道如何解释您最初写的 Submission class。所以它只是简单地创建一个 Submission 对象的列，当它写入时，它使用默认为 object __str__ 的 str(Submission()) 因为你没有定义另一个 __str__。真的，你想使用一个序列。 namedtuple 函数实际上是一个 class 工厂 ，它创建了一个从 tuple 派生的记录类型，因此它具有所有方便的函数需要一个非常方便的构造函数。

现在，由于您使用的是 Python 2，所以我没有费心去更改您对 pandas 的使用，尽管仅将其用于编写 csv 似乎有些过分。话虽这么说，让 Python 2 csv 模块与 unicode 兼容是一件很痛苦的事情，所以你最好保留它。如果你可以切换到 Python 3，你可以简单地将 pandas 替换为：

import csv
with open(filename, 'w', newline='', encoding='utf8') as f:
    writer = csv.writer(f)
    writer.writerow(Submission._fields) # namedtuple breaks convention public fields have single underscore
    writer.writerows(data)

将对象列表写入 csv 文件

Writing list of objects to csv file

python

csv

python-2.7

praw