如何從python中的陣列物件中提取鍵的值

這可能是一個真正的菜鳥問題。

感謝您的幫助。

我正在接收具有以下結構的 json 有效負載

 {
    "response": true,
    "error": null,
    "msg": null,
    "data": {
        "slots": {
            "04/26/2022": [
                {
                    "0": 1650958200000,
                    "1": 19800,
                    "3": "1:00 PM",
                    "4": "26/Apr/2022 13:00 IST"
                },
                {
                    "0": 1650960000000,
                    "1": 19800,
                    "3": "1:30 PM",
                    "4": "26/Apr/2022 13:30 IST"
                },
                {
                    "0": 1650963600000,
                    "1": 19800,
                    "3": "2:30 PM",
                    "4": "26/Apr/2022 14:30 IST"
                },
                {
                    "0": 1650965400000,
                    "1": 19800,
                    "3": "3:00 PM",
                    "4": "26/Apr/2022 15:00 IST"
                },
                {
                    "0": 1650967200000,
                    "1": 19800,
                    "3": "3:30 PM",
                    "4": "26/Apr/2022 15:30 IST"
                }
            ],
            "04/24/2022": [],
            "04/25/2022": [],
            "04/23/2022": []
        }
    }
}

我想創建一個具有“0”值陣列的新物件。輸出應該是

{
 "slots": [
          1650958200000,
          1650960000000,
          1650963600000,
          1650965400000,
          1650967200000
          ]
}

我該怎么做呢？

uj5u.com熱心網友回復：

這是一個直截了當的方法：

slots = payload["data"]["slots"]  # Assumes payload has been converted from JSON to Python

slots_obj = {"slots": [d["0"] for _, lst in slots.items() for d in lst]}

輸出：

{'slots': [1650958200000,
           1650960000000,
           1650963600000,
           1650965400000,
           1650967200000,
           16539137693178]}

如果您還沒有，請使用json.loads將 JSON 轉換為 Python 字典：

import json

payload = json.loads(payload)

上面的解決方案使用了所謂的串列理解。相當于一個for回圈，可能更容易理解：

timestamps = []  # Initialize an empty list to accumulate the Unix timestamps

# Iterate over each date, array pair in the slots dictionary using slots.items()
for _, slot_array in slots.items():
    # Iterate over each inner dictionary
    for slot_dict in slot_array:
        # Grab the value at the "0" and append it to the timestamps accumulator
        timestamps.append(slot_dict["0"])

# Finally create the new object, a dictionary with one key, "slots"
slots_obj = {"slots": timestamps}

uj5u.com熱心網友回復：

使用's 方法json中的模塊ddejohn將比此處顯示的方法更有效。但是，我認為查看獲得所需輸出的其他方法對您很有用。

如果上面是一個字串，比如說，，s你可以findall()從re模塊中使用來提取這些數字。

import re

p = re.compile(r'(?<="0": )\d (?=,)')
d = {'slots': [int(x) for x in p.findall(s)]}

print(d)

輸出

{'slots': [1650958200000,
           1650960000000,
           1650963600000,
           1650965400000,
           1650967200000]}

正則運算式r'(?<="0": )\d (?=,)'匹配一個或多個前面"0": 和后面跟著 a 的數字,。findall(s)將字串中此運算式的所有（非重疊）匹配項s作為字串串列回傳。特別是，p.findall(s)回傳串列

['1650958200000',
 '1650960000000',
 '1650963600000',
 '1650965400000',
 '1650967200000']

[int(x) for x in p.findall(s)]通過獲取回傳的串列的每個元素p.findall(s)并將其轉換為整數來創建一個新串列。

計時

像 in 的方法那樣使用json模塊ddejohn會更有效。

# ddejohn
6.14 μs ± 41 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)

# oda
14.6 μs ± 76.1 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)

uj5u.com熱心網友回復：

我做了下一個程式，希望對你有用。

但是您應該記住，您可能會丟失重要資訊

它的作業原理在程式中的解釋

import json

dicc={}

# We open the file
with open('data.json', 'r') as f:
    data = json.JSONDecoder().decode(f.read())

    # We get the data
    slots=data['data']['slots']

    # We travel to the slots and we get the key
    for slot in slots:

        # We get the data and put them in the dictionary
        for key in slots[slot]:

            # If slots key is not created, we create it
            if "slots" not in dicc:

                # We create the list that will contain the data
                dicc["slots"]=[]

            #We add the data to the list in the dictionary
            dicc["slots"].append(key['0'])

new_json=json.dumps(dicc)

標籤：Python json for循环

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