python - 按键分组并创建相应值的列表

Question

我想将我的字典转换成这种格式。我曾尝试使用 groupby 但无法达到预期的格式。

input = [
         {'algorithms': 'BLOWFISH', 'dcount': 5.8984375},
         {'algorithms': 'AES-256', 'dcount': 5.609375},
         {'algorithms': 'AES-256', 'dcount': 9.309375},
         {'algorithms': 'RSA', 'dcount': 8.309375},
         {'algorithms': 'BLOWFISH','dcount': 6.309375}
        ]

预期输出:

  output = [
  {
    name: "BLOWFISH",
    data: [5.8984375,6.309375]
  },
  {
    name: "AES-256",
    data: [5.609375,9.309375]
  },
  {
    name: 'RSA',
    data: [8.309375]
  }
]

Answer 1

您需要排序 input之前 itertools.groupby 将工作:

The operation of groupby() is similar to the uniq filter in Unix. Itgenerates a break or new group every time the value of the keyfunction changes (which is why it is usually necessary to have sortedthe data using the same key function). That behavior differs fromSQL’s GROUP BY which aggregates common elements regardless of theirinput order.

from itertools import groupby
import json

input = [
   {
        "algorithms": "BLOWFISH",
        "dcount": 5.8984375
   },
   {
        "algorithms": "AES-256",
        "dcount": 5.609375
   },
   {
        "algorithms": "AES-256",
        "dcount": 9.309375
   },
   {
        "algorithms": "RSA",
        "dcount": 8.309375
   },
   {
        "algorithms": "BLOWFISH",
        "dcount": 6.309375
   }
]

output = [
    {
        "name": k,
        "data": [d["dcount"] for d in g]
    } 
    for k, g in groupby(sorted(input, key=lambda d: d["algorithms"]),
                        key=lambda d: d["algorithms"])
]

print(json.dumps(output, indent=4))

输出:

[
    {
        "name": "AES-256",
        "data": [
            5.609375,
            9.309375
        ]
    },
    {
        "name": "BLOWFISH",
        "data": [
            5.8984375,
            6.309375
        ]
    },
    {
        "name": "RSA",
        "data": [
            8.309375
        ]
    }
]