Python使用itertools.chain合并数据后调用order_by报错：'list'对象没有'order_by'属性

Hey there, let's break down why you're hitting that AttributeError and fix it right away!

The Root Cause #

Once you convert the output of itertools.chain to a list with list(), you're working with a plain Python list—not a Django QuerySet. The order_by() method is a QuerySet-exclusive feature, so calling it on a list will throw that error every time.

The Fix #

Since data1 and data2 are lists of serialized dictionaries, you'll need to use Python's built-in sorted() function to sort them. Here's how to adjust your code:

from itertools import chain

# Combine the two lists first (no need to wrap in list() yet if we sort immediately)
all_results = sorted(chain(data1, data2), key=lambda x: x['created_on'], reverse=True)

What This Does #

• chain(data1, data2) merges your two lists into a single iterable (avoids creating an extra list upfront if you sort right away)
• key=lambda x: x['created_on'] tells Python to sort each dictionary by its created_on value. Since your timestamps are in ISO 8601 format (like "2021-01-09T06:32:30.381712Z"), string comparison works perfectly here—lex order matches chronological order.
• reverse=True gives you the descending sort (newest items first) you wanted, just like using -created_on in a QuerySet.

Optional: If You Prefer Two Separate Steps #

If you want to keep the merged list and sort it separately, that works too:

all_results = list(chain(data1, data2))
all_results_sorted = sorted(all_results, key=lambda x: x['created_on'], reverse=True)

This will give you the sorted list of combined conversation and file records you're expecting.

内容的提问来源于stack exchange，提问作者anonymoususer