Question

我是新手，如果这是一个重复的问题，我无法提前给出答案。

我正在访问历史金属价格api，它会返回列表字典。列表中的第一项是列名，其余的是属于这些列标题的数据。

我正在尝试编写将返回记录中所有日期的日期和现金买方值的代码。

这是我到目前为止所写的内容。我已经尝试了几种字典和列表方法，并且无法使其工作。我确定是我。

此帖子的URL有意限制为1行（行= 1），并删除了我的API密钥。但是，此URL适用于任何人，但在没有API密钥的情况下速率受限：

import urllib
import json
url = "https://www.quandl.com/api/v1/datasets/LME/PR_CU.json?rows=1"
response = urllib.urlopen(url)
data = json.loads(response.read())

这是一个示例输出：

{
"code": "PR_CU",
"column_names": [
    "Date",
    "Cash Buyer",
    "Cash Seller & Settlement",
    "3-months Buyer",
    "3-months Seller",
    "15-months Buyer",
    "15-months Seller",
    "Dec 1 Buyer",
    "Dec 1 Seller",
    "Dec 2 Buyer",
    "Dec 2 Seller",
    "Dec 3 Buyer",
    "Dec 3 Seller"
],
"data": [
    [
        "2016-10-14",
        4672.0,
        4672.5,
        4691.0,
        4692.0,
        4730.0,
        4740.0,
        null,
        null,
        null,
        null,
        null,
        null
    ]
],
"description": "LME Official Prices i
"display_url": null,
"errors": {},
"frequency": "daily",
"from_date": "2012-01-03",
"id": 19701916,
"name": "Copper Prices",
"premium": false,
"private": false,
"source_code": "LME",
"source_name": "London Metal Exchange"
"to_date": "2016-10-14",
"type": null,
"updated_at": "2016-10-17T07:05:00.54
"urlize_name": "Copper-Prices"
}

感谢您的帮助，我

Answer 1

一种方法是获得＆＃39;日期＆＃39;和＆＃39;缓存买家＆＃39;列，然后遍历JSON的 data 部分。

我将在我的示例中将您从JSON加载的字典命名为字典：

# Get the columns and the data part of the response dictionary
columns = dictionary['column_names']
data = dictionary['data']

# This is done in case that the columns are not always in the same order
# if they are, you can just hardcode the values to 0 and 1
index_of_date = columns.index('Date')
index_of_cash_buyer = columns.index('Cash Buyer')

# As data section is a list of lists we need to
# iterate through lists of data and collect the desired values
for piece_of_data in data:
    date = piece_of_data[index_of_date]
    cash_buyer = piece_of_data[index_of_cash_buyer]
    print date, cash_buyer

用于获取数据和检索列名的Python JSON列表

1 个答案: