擅长:python、mysql、java
<pre><code>from collections import defaultdict
d = defaultdict(list)
for x in a:
d[x['id']].append(x['desc']) # group description by id
b = [dict(id=id, desc=desc if len(desc) > 1 else desc[0])
for id, desc in d.items()]
</code></pre>
<p>维护秩序:</p>
<pre><code>b = []
for id in (x['id'] for x in a):
desc = d[id]
if desc:
b.append(dict(id=id, desc=desc if len(desc) > 1 else desc[0]))
del d[id]
</code></pre>