如何从json中提取元素的最新时间戳，而不考虑大小写

Question

下面有一个字典列表

rec=[{
'Name': 'aRe',
'Email': '[e-mail]',
'timestamp': '2021-11-29T04:33:28.138522Z'
},
{
'Name': 'Umar',
'Email': '[e-mail]',
'timestamp': '2021-11-28T04:33:28.138522Z'
},

{
'Name': 'Are',
'Email': '[e-mail]',
'timestamp': '2021-11-27T04:33:28.138522Z'
},

{
'Name': 'arE',
'Email': '[e-mail]',
'timestamp': '2021-11-28T06:59:58.975864Z'
},
{
'Name': 'umaR',
'Email': '[e-mail]',
'timestamp': '2021-11-29T04:33:28.138522Z'
},
{
'Name': 'Sc',
'Email': '[e-mail]',
'timestamp': '2022-02-01T15:02:12.301701Z'
}
]

• 如果存在重复id，则提取具有最新时间戳的字典

预计出来

[{'Name': 'umaR',
'Email': '[e-mail]',
'timestamp': '2021-11-29T04:33:28.138522Z'},
{'Name': 'aRe',
'Email': '[e-mail]',
'timestamp': '2021-11-29T04:33:28.138522Z'},
{'Name': 'Sc',
'Email': '[e-mail]',
'timestamp': '2022-02-01T15:02:12.301701Z'}]

代码在

下面

from itertools import groupby
filtered_recs = []
for key, group_iter in groupby(recs, lambda rec: rec['Name'].lower()):
recent_rec = max(group_iter, key = lambda rec: rec['timestamp'])
filtered_recs.append(recent_rec)
filtered_recs

我的代码工作良好，如果所有的'名称'在同一情况下。像name一样，'are'， 'umar'， 'sc'不适用不规则大小写字母

Answer 1

先对recs排序:

from itertools import groupby
filtered_recs = []
recs = sorted(recs, key=lambda rec: rec["Name"].lower())  # <-- sort before groupby
for key, group_iter in groupby(recs, lambda rec: rec["Name"].lower()):
recent_rec = max(group_iter, key=lambda rec: rec["timestamp"])
filtered_recs.append(recent_rec)
print(filtered_recs)

打印:

[
{
"Name": "aRe",
"Email": "[e-mail]",
"timestamp": "2021-11-29T04:33:28.138522Z",
},
{
"Name": "Sc",
"Email": "[e-mail]",
"timestamp": "2022-02-01T15:02:12.301701Z",
},
{
"Name": "umaR",
"Email": "[e-mail]",
"timestamp": "2021-11-29T04:33:28.138522Z",
},
]

---

EDIT: Version without sort:

filtered_recs = {}
for r in recs:
filtered_recs.setdefault(r["Name"].lower(), []).append(r)
for k, v in filtered_recs.items():
filtered_recs[k] = max(v, key=lambda rec: rec["timestamp"])
print(list(filtered_recs.values()))

打印:

[
{
"Name": "aRe",
"Email": "[e-mail]",
"timestamp": "2021-11-29T04:33:28.138522Z",
},
{
"Name": "umaR",
"Email": "[e-mail]",
"timestamp": "2021-11-29T04:33:28.138522Z",
},
{
"Name": "Sc",
"Email": "[e-mail]",
"timestamp": "2022-02-01T15:02:12.301701Z",
},
]